FORM 2 THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION [See section 10, Rule 13] RARE EARTH SINTERED MAGNET, METHOD FOR PRODUCING RARE EARTH SINTERED MAGNET, ROTOR, AND ROTARY MACHINE MITSUBISHI ELECTRIC CORPORATION A CORPORATION ORGANISED AND EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 1008310, JAPAN THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED. 2 DESCRIPTION Field [0001] The present disclosure relates to a rare earth sintered magnet which is a permanent magnet obtained by5 sintering a material containing a rare earth element, a method for producing a rare earth sintered magnet, a rotor, and a rotary machine. Background10 [0002] R-T-B-based permanent magnets having a tetragonal R2T14B intermetallic compound as a main phase are known. Here, R is a rare earth element, T is a transition metal element such as Fe (iron) or Fe that is partially replaced by cobalt (Co), and B is boron. R-T-B-based permanent magnets are15 used for various components having a high added value, including for example industrial motors. In particular, Nd- Fe-B-based sintered magnets in which R is neodymium (Nd) are used for various components due to excellent magnetic properties. In addition, because industrial motors are often20 used in a high temperature environment exceeding 100°C, attempts have been made to improve coercive force by adding heavy rare earth elements such as dysprosium (Dy) to Nd-T- B-based sintered magnets. [0003] In recent years, the production of Nd-Fe-B-based25 sintered magnets has been expanded, and the consumption of Nd and heavy rare earth elements such as Dy and terbium (Tb) has been increased. However, Nd and heavy rare earth elements are expensive and also have a procurement risk due to high distribution unevenness. In view of this, a possible30 measure for reducing the consumption of Nd and heavy rare earth elements is to use a magnet that forms a main phase including a low heavy rare earth phase, to use other rare 3 earth elements as R, such as praseodymium (Pr), cerium (Ce), lanthanum (La), samarium (Sm), scandium (Sc), gadolinium (Gd), yttrium (Y), and lutetium (Lu), or to use a special production method such as subjecting a sintered body to hot plastic working. Hereinafter, hot plastic working applied5 to a sintered body is referred to as hot working. However, adding a heavy rare earth element to the main phase to no small extent contributes to improvement of the coercive force, but significantly degrades the residual magnetic flux density. In addition, replacing all or a part of Nd with10 elements such as Pr, Ce, La, Sm, Sc, Gd, Y, and Lu significantly degrades the magnetic properties of the residual magnetic flux density and the coercive force. Furthermore, subjecting the sintered body to hot working significantly degrades the magnetization of the magnet due15 to the refinement of the crystal grains. From the above, it has been difficult to achieve both saving of heavy rare earth elements and excellent magnetic properties and magnetization. Therefore, attempts have been conventionally made to develop technology that allows for improvement of magnetic20 properties at room temperature and prevention of degradation of magnetic properties associated with temperature rise in the case of using these elements for producing Nd-Fe-B-based sintered magnets. In particular, at present, a rare earth magnet that allows for both further reduction of heavy rare25 earth elements and excellent magnetic properties and magnetization is required. [0004] Patent Literature 1 discloses an R-T-B-based sintered magnet containing main phase grains consisting of an R2T14B crystal, where R is one or more kinds of rare earth30 elements including a heavy rare earth element RH as an essential element, T is one or more kinds of transition metal elements including Fe or including Fe and Co as an essential 4 element, B is boron. A part of the main phase grains of the R-T-B-based sintered magnet includes a plurality of low heavy rare earth element crystal phases therein, and the low heavy rare earth element crystal phase is a phase consisting of an R2T14B crystal and having a relatively low concentration of5 the heavy rare earth element with respect to the concentration of the heavy rare earth element in the entire main phase grains. According to the technique described in Patent Literature 1, it is possible to obtain an R-T-B-based sintered magnet having improved magnetic properties at low10 cost. [0005] Patent Literature 2 discloses a method for producing a rare earth magnet consisting of: a first step of producing a sintered body represented by a composition formula of (R11-xR2x)aTMbBcMd and having a structure consisting15 of a main phase and a grain boundary phase; a second step of producing a rare earth magnet precursor by subjecting the sintered body to hot working; and a third step of producing a rare earth magnet from the rare earth magnet precursor by causing a melt of an R3-M modified alloy to be diffused and20 permeating through the grain boundary phase of the rare earth magnet precursor. Here, R1 is one or more rare earth elements including Y, R2 is a rare earth element different from R1, TM is a transition metal including one or more of Fe, nickel (Ni), and Co, B is boron, and M is one or more of25 titanium (Ti), gallium (Ga), zinc (Zn), silicon (Si), aluminum (Al), niobium (Nb), zirconium (Zr), Ni, Co, manganese (Mn), vanadium (V), tungsten (W), tantalum (Ta), germanium (Ge), copper (Cu), chromium (Cr), hafnium (Hf), molybdenum (Mo), phosphorus (P), carbon (C), magnesium (Mg),30 mercury (Hg), silver (Ag), and gold (Au). Further, x, a, b, c, and d satisfy 0.01≤x≤1, 12≤a≤20, b=100−a−c−d, 5≤c≤20, and 0≤d≤3, all by at%. R3 is a rare earth element including R1 5 and R2. According to the technique described in Patent Literature 2, it is possible to produce a rare earth magnet excellent in not only magnetization but also coercive force performance even when the main phase ratio is high. 5 Citation List Patent Literature [0006] Patent Literature 1: Japanese Patent Application Laid-open No. 2018-174313 Patent Literature 2: Japanese Patent Application10 Laid-open No. 2015-153813 Summary of Invention Problem to be solved by the Invention [0007] However, in the R-T-B-based sintered magnet15 described in Patent Literature 1, a phase including a heavy rare earth element is present in the main phase, which improves coercive force but cannot yield the residual magnetic flux density required for industrial motors or the like, which may lead to degradation of magnetic properties.20 Furthermore, since heavy rare earth elements are used, there is a problem that the procurement risk and cost cannot be reduced. Even if the rare earth magnet produced with the production method described in Patent Literature 2 can reduce heavy rare earth elements and improve the coercive force,25 the production method includes hot working. For this reason, there is a possibility of lowering the residual magnetic flux density and magnetization of the rare earth magnet to be produced. [0008] The present disclosure has been made in view of30 the above, and an object thereof is to obtain a rare earth sintered magnet capable of improving magnetic properties and magnetization as compared with the related art, while 6 reducing use of Nd and heavy rare earth elements as compared with the related art. Means to Solve the Problem [0009] In order to solve the above-described problems and5 achieve the object, a rare earth sintered magnet according to the present disclosure includes a main phase that satisfies a general formula (Nd, Pr, R)-Fe-B, where R is one or more rare earth elements selected excluding Nd and Pr, the main phase containing crystal grains based on an Nd2Fe14B10 crystal structure. The main phase includes a core portion and a shell portion covering the core portion. The main phase includes a first main phase that satisfies CNd>CPr and a second main phase that satisfies CNdCPr and a second main phase25 12 that satisfies CNdCPr is satisfied in the core portion 11c of the first main phase 11, and CNdCPr and the second main phase 12 that satisfies CNdC2Nd and C1PrCPr is present more than the second main phase5 12 each of which satisfies CNdSNd and CPrSPr, where SNd is the concentration of Nd in the shell portions 11s and 12s and25 SPr is the concentration of Pr in the shell portions 11s and 12s. Specifically, the shell portion 11s of the first main phase 11 has a higher concentration of Pr than the core portion 11c instead of having a lower concentration of Nd, and the shell portion 12s of the second main phase 12 has a30 higher concentration of Nd than the core portion 12c instead of having a lower concentration of Pr. By forming the first main phase 11 including the shell portion 11s having a high 12 concentration of Pr in the main phase 10, the coercive force can be improved. Furthermore, by forming the second main phase 12 including the shell portion 12s having a high concentration of Nd in the main phase 10, it is possible to prevent degradation of the residual magnetic flux density5 while maintaining the coercive force. Through selective control to achieve such a structure form, the rare earth sintered magnet 1 can exhibit excellent magnetic properties as compared with the related art. [0019] Further, the average grain size of the crystal10 grains of the main phase 10 is preferably 100 μm or less, and more preferably 0.5 μm to 50 μm for improving magnetic properties. Furthermore, setting the average grain size to about 1 μm to 10 μm results in a grain size different from the microstructure produced by hot working, leading to the15 rare earth sintered magnet 1 that maintains good magnetizing ability and has excellent magnetic properties as compared with the related art. [0020] The rare earth sintered magnet 1 according to the first embodiment may contain an additive element M that20 further improves magnetic properties. The additive element M is one or more elements selected from the group consisting of Ga, Cu, Al, Co, Zr, Ti, Nb, Dy, Tb, Mn, Gd, and Ho (holmium). Therefore, the rare earth sintered magnet 1 according to the first embodiment is expressed by the general25 formula (NdaPrbRc)FedBeMf, where the additive element M is one or more elements selected from the group consisting of Ga, Cu, Al, Co, Zr, Ti, Nb, Dy, Tb, Mn, Gd, and Ho. It is desirable that a, b, c, d, e, and f satisfy the following relational expressions.30 [0021] 5≤a+b≤20 0CPr and the second main phase 12 that satisfies CNdC2Nd and20 C1PrSNd and CPrSPr. This also makes it possible to obtain the rare earth sintered magnet 1 in which magnetic properties and magnetization are improved, while reducing use of Nd and heavy rare earth elements. [0024] Second Embodiment.30 FIG. 2 is a diagram schematically illustrating an exemplary sintered structure of a rare earth sintered magnet according to the second embodiment. The rare earth sintered 14 magnet 1 according to the second embodiment includes the main phase 10 and the subphase 20. The main phase 10 includes the first main phase 11 and the second main phase 12 as described in the first embodiment, but in FIG. 2, the first main phase 11 and the second main phase 12 are collectively5 denoted by the main phase 10. The subphase 20 is present between the main phases 10. [0025] In the rare earth sintered magnet 1 according to the second embodiment, a case where La and Sm are selected as the element R will be described. In a case where La and10 Sm are selected as the element R, the effect of improving the magnetic properties and having excellent magnetization as compared with the related art, while reducing use of Nd and heavy rare earth elements, is further enhanced. In this example, the main phase 10 has the composition formula15 (Nd,Pr,La,Sm)2Fe14B. The reason why the element R of the rare earth sintered magnet 1 having a tetragonal R2Fe14B crystal structure is rare earth elements including La and Sm is that the calculation of magnetic interaction energy with the use of a molecular orbital method shows that a20 composition in which La and Sm are added can produce the rare earth sintered magnet 1 which is suitable for practical use in that degradation of magnetic properties associated with temperature rise can be significantly prevented. In addition, by intentionally segregating La and Sm also in the25 grain boundary, which is an example of the subphase 20, it is possible to cause Nd and Pr to be relatively diffused throughout the main phase 10, resulting in enhanced magnetocrystalline anisotropy of the main phase 10. As a result, a core-shell structure in which a portion having30 high magnetic anisotropy and a portion having low magnetic anisotropy exist in the main phase 10 is formed, and a state in which the rare earth sintered magnet 1 in which the first 15 main phase 11 that satisfies CNd>CPr and the second main phase 12 that satisfies CNd(C+D) is preferably satisfied, where A, B, C, and D are the composition ratios of Nd, Pr, La, and Sm, respectively.10 [0027] In the rare earth sintered magnet 1 according to the second embodiment, given R=La and/or Sm, the rare earth sintered magnet 1 includes the subphase 20 in addition to the first main phase 11 and the second main phase 12 in the first embodiment. The subphase 20 includes a crystalline15 first subphase 21 based on an oxide phase having a main component represented by (Nd, Pr, La, Sm)-O, and a crystalline second subphase 22 having a main component represented by (Nd, Pr, La)-O. The concentration of Sm in the subphase 20 is higher in the first subphase 21 than in20 the second subphase 22. This achieves the effect of preventing not only degradation of the magnetic properties at room temperature but also degradation of the magnetic properties associated with temperature rise. [0028] Here, “the concentration of Sm is higher in the25 first subphase 21 than in the second subphase 22” means that the detection intensity of Sm is higher on average in the first subphase 21 than in the second subphase 22 by mapping analysis using EPMA. [0029] The crystalline subphase 20 is a generic name for30 the crystalline first subphase 21 and the crystalline second subphase 22, and is present between the main phases 10. The crystalline first subphase 21 is represented by (Nd, Pr, La, 16 Sm)-O, and the crystalline second subphase 22 is represented by (Nd, Pr, La)-O. Here, (Nd, Pr, La, Sm) means that a part of Nd and Pr is replaced by La and Sm. Note that the elements of the main components are described in parentheses; therefore, the first subphase 21 and the second subphase 225 may contain a small amount of another component, in addition to the elements indicated in parentheses. In one example, the second subphase 22 represented by (Nd,Pr,La)-O contains an extremely small amount of Sm. [0030] In the rare earth sintered magnet 1 according to10 the second embodiment, there is a concentration difference of La and Sm between the main phase 10 and the subphase 20, and La and Sm are segregated in the subphase 20 more than in the main phase 10. That is, the sum of the concentrations of La in the first subphase 21 and the second subphase 22 is15 equal to or greater than the concentration of La in the main phase 10, and the sum of the concentrations of Sm in the first subphase 21 and the second subphase 22 is equal to or greater than the concentration of Sm in the main phase 10. Specifically, the concentrations of La and Sm in the subphase20 20 are equal to or higher than the concentrations of La and Sm in the main phase 10. Here, the concentration of La of the main phase 10 is the sum of the concentration of La of the first main phase 11 and the concentration of La of the second main phase 12. That is, the sum of the concentrations25 of La in the first subphase 21 and the second subphase 22 is higher than the sum of the concentrations of La in the first main phase 11 and the second main phase 12. Here, the concentration of Sm of the main phase 10 is the sum of the concentration of Sm of the first main phase 11 and the30 concentration of Sm of the second main phase 12. That is, the sum of the concentrations of Sm in the first subphase 21 and the second subphase 22 is higher than the sum of the 17 concentrations of Sm in the first main phase 11 and the second main phase 12. [0031] Here, given that X represents the concentration of La contained in the main phase 10, X1 represents the concentration of La contained in the first subphase 21, X25 represents the concentration of La contained in the second subphase 22, Y represents the concentration of Sm contained in the main phase 10, Y1 represents the concentration of Sm contained in the first subphase 21, and Y2 represents the concentration of Sm contained in the second subphase 22, the10 relationship of Formula (1) below is satisfied. [0032] 1<(Y1+Y2)/Y<(X1+X2)/X •••• (1) [0033] Furthermore, from the viewpoint of improving the magnetic properties, the relationships of Formulas (2) and (3) below are satisfied with respect to the concentrations15 of Nd and Pr contained in the main phase 10. [0034] (CNd+SNd)>(X+Y) •••• (2) (CPr+SPr)>(X+Y) •••• (3) [0035] In the above description, the concentration of La in the main phase 10 is the sum of the concentrations of La20 in the first main phase 11 and the second main phase 12, and the concentration of Sm in the main phase 10 is the sum of the concentrations of Sm in the first main phase 11 and the second main phase 12. This indicates that both La and Sm are segregated in the subphase 20 more than in the main phase25 10. However, when viewed locally, each of the sum of the concentrations of La and Sm in the first main phase 11 and the second main phase 12 and each of the sum of the concentrations of La and Sm in the first subphase 21 and the second subphase 22 may not satisfy the above relationship.30 Therefore, more specifically, the concentration of La in the main phase 10 indicates the average of the concentrations of La in the first main phase 11 and the second main phase 12, 18 and the concentration of Sm in the main phase 10 indicates the average of the concentrations of Sm in the first main phase 11 and the second main phase 12. In this case, the concentration of La of the subphase 20, that is, the sum of the concentrations of La in the first subphase 21 and the5 second subphase 22 means the average of the concentrations of La in the first subphase 21 and the second subphase 22, and the concentration of Sm of the subphase 20, that is, the sum of the concentrations of Sm in the first subphase 21 and the second subphase 22 means the average of the10 concentrations of Sm in the first subphase 21 and the second subphase 22. [0036] La is present at a high concentration in the grain boundary in the process of production, particularly in the heat treatment, whereby Nd and Pr are relatively diffused15 throughout the main phase 10. As a result, in the rare earth sintered magnet 1 according to the second embodiment, Nd and Pr in the main phase 10 are not consumed at the grain boundary, leading to improved magnetocrystalline anisotropy. Sm is also present at a higher concentration in the subphase 20,20 particularly in the first subphase 21, than in the main phase 10, whereby Nd is relatively diffused throughout the main phase 10 as in the case of La, resulting in improved magnetocrystalline anisotropy. [0037] Next, at which atomic sites of the tetragonal25 R2Fe14B crystal structure La and Sm are substituted will be described. FIG. 3 is a diagram illustrating atomic sites in a tetragonal Nd2Fe14B crystal structure. Note that the crystal structure illustrated in FIG. 3 is described, in one example, in FIG. 1 of Reference Literature 1 shown below.30 The sites of substitution are determined from the numerical value of the stabilization energy associated with substitution computed using band calculation and molecular 19 field approximation based on the Heisenberg model. (Reference Literature 1): J. F. Herbst et al., “Relationships between crystal structure and magnetic properties in Nd2Fe14B”, PHYSICAL REVIEW B. 1984, Vol. 29, No. 7, p. 4176– 4178.5 [0038] First, a method for calculating stabilization energy in La will be described. The stabilization energy in La can be computed as the energy difference between (Nd7La1)Fe56B4+Nd and Nd8(Fe55La1)B4+Fe using Nd8Fe56B4 crystal cells. The smaller the energy value, the more stable it is10 when the atom is substituted at that site. That is, La is likely to be substituted at an atomic site having the smallest energy among the atomic sites. This calculation assumes that substituting La for the original atom does not change the lattice constant in the tetragonal R2Fe14B crystal15 structure due to the difference in atomic radius. Table 1 shows the stabilization energy of La at each substitution site at various environmental temperatures. [0039] [Table 1] 20 20 [0040] Table 1 indicates that stable substitution sites for La are Nd (f) sites at temperatures of 1000K and higher, and Fe (c) sites at temperatures of 293K and 500K. As will be described later, the raw material of the rare earth sintered magnet 1 according to the second embodiment is5 heated and melted at a temperature of 1000K or higher and then rapidly cooled. Therefore, it is considered that the raw material of the rare earth sintered magnet 1 is maintained in a state of 1000K or higher, that is, 727°C or higher, and more preferably about 1300K, that is, 1027°C.10 In this case, La is considered to be substituted at Nd (f) sites or Nd (g) sites. Here, La is considered to be preferentially substituted at energetically stable Nd (f) sites, but may be substituted at Nd (g) sites having a small energy difference among the substitution sites for La. This15 is why Nd (g) sites are also mentioned as a candidate for the substitution sites for La. [0041] Furthermore, when the rare earth sintered magnet 1 is produced with the production method described later, the temperature is 1000K or higher at the time of sintering,20 but the Fe (c) sites described in Table 1 are held in an energetically stable temperature zone repeatedly through the primary aging step, the secondary aging step, the tertiary aging step, the quaternary aging step, and the cooling step. In other words, the substitution of La at Nd sites of the25 main phase 10 is maintained in an unstable energy state. That is, La is mainly substituted at Nd sites of the main phase 10 in the raw material stage of the rare earth sintered magnet 1; however, in the rare earth sintered magnet 1 produced with the production method described later, by30 intentionally holding the Nd sites of the main phase 10 repeatedly in a temperature range in an unstable energy state, a certain amount of La is selectively released from the Nd 21 sites of the main phase 10, and as a result, La is segregated in the subphase 20. As a result, the main phase 10 promotes the formation of the characteristic structure, namely the core-shell structure. [0042] Next, a method for calculating stabilization5 energy in Sm will be described. The stabilization energy of Sm can be computed as the energy difference between (Nd7Sm1)Fe56B4+Nd and Nd8(Fe55Sm1)B4+Fe. Similarly to the case of La, atomic substitution does not change the lattice constant in the tetragonal R2Fe14B crystal structure. Table10 2 shows the stabilization energy of Sm at each substitution site at various environmental temperatures. [0043] [Table 2] [0044] Table 2 indicates that stable substitution sites15 for Sm are Nd (g) sites at any temperature, unlike in the case of La. Sm is also considered to be preferentially substituted at energetically stable Nd (g) sites, but may be substituted at Nd (f) sites having a small energy difference 22 among the substitution sites for Sm. [0045] When the rare earth sintered magnet 1 is produced with the production method described later, substitution at Nd (g) sites of the main phase 10 is most stable in terms of energy. However, as described above, holding in a5 temperature range where the substitution of La at Nd sites of the main phase 10 is unstable causes a part of Sm to be released from the Nd sites of the main phase 10 together with La and segregated in the subphase 20. As a result, the concentrations of La and Sm differ between the main phase 1010 and the subphase 20: the sum of the concentrations of La in the first subphase 21 and the second subphase 22 is equal to or greater than the concentration of La in the main phase 10, and the sum of the concentrations of Sm in the first subphase 21 and the second subphase 22 is equal to or greater15 than the concentration of Sm in the main phase 10. More specifically, the average of the concentrations of La in the first subphase 21 and the second subphase 22 is equal to or greater than the average of the concentrations of La in the first main phase 11 and the second main phase 12, and the20 average of the concentrations of Sm in the first subphase 21 and the second subphase 22 is equal to or greater than the average of the concentrations of Sm in the first main phase 11 and the second main phase 12. That is, La and Sm can be said to be segregated in the subphase 20.25 [0046] Comparing La and Sm, La held in a temperature range in an unstable energy state is overwhelmingly more likely to be segregated in the subphase 20 from the viewpoint of energy. As a result, in the case of the rare earth sintered magnet 1 prepared with almost the same concentrations of La and Sm,30 comparing La and Sm present in the rare earth sintered magnet 1, La has a larger segregation ratio to the subphase 20. By being held repeatedly in this temperature region, the 23 subphase 20 produces a concentration difference in Sm that has a small segregation ratio, and the first subphase 21 and the second subphase 22 are formed. This promotes the formation of the core-shell structure in the main phase 10. [0047] Here, Nd is representatively described as5 illustrated in FIG. 3, but Nd and Pr are produced as a mixture as represented by didymium (Di), and thus it is considered that the energy levels of Nd and Pr are close to each other. Therefore, the same applies to a case where Nd is replaced with Pr. As the two types of Nd and Pr are10 present, the main phase 10 having two types of core-shell structures can be formed. [0048] As described above, the rare earth sintered magnet 1 according to the second embodiment includes the main phase 10 that satisfies a general formula (Nd, Pr, R)-Fe-B, where15 R is one or more rare earth elements selected excluding Nd and Pr, the main phase 10 containing crystal grains based on an Nd2Fe14B crystal structure, wherein the main phase 10 includes a core portion and a shell portion covering the core portion, and given R=La and/or Sm, the rare earth20 sintered magnet 1 includes the subphase 20 in addition to the first main phase 11 and the second main phase 12 described in the first embodiment. The subphase 20 includes the crystalline first subphase 21 having a main component based on an oxide phase represented by (Nd, Pr, La, Sm)-O25 and the crystalline second subphase 22 having a main component represented by (Nd, Pr, La)-O, and the concentration of Sm is higher in the first subphase 21 than in the second subphase 22. That is, the two types of main phases 10 and the two types of subphases 20 exist. As a30 result, it is possible to provide the rare earth sintered magnet 1 having excellent magnetic properties, such as temperature properties of magnetic properties, as compared 24 with the related art. In addition, by setting R to La and Sm, the main phase 10 is in a state in which the first main phase 11 that satisfies CNd>CPr and the second main phase 12 that satisfies CNdCPr and the second5 main phase 12 consisting of CNdCPr and the second main phase 12 consisting of CNdCPr and the second25 main phase 12 that satisfies CNdCPr and the second main phase 12 that satisfies CNdCPr and the second main phase 12 that satisfies CNdCPr is larger than the number of second main phases 125 that are CNdSNd and CPrSPr.10 [0096] Next, the results of measurement of the magnetic properties in each sample according to Examples 1 to 8 and Comparative Examples 1 to 12 will be described. The shape of each sample that is the subject of magnetic measurement is a block shape having a length, a width, and a height of15 7 mm. The first measurement temperature T1 is 23°C, and the second measurement temperature T2 is 200°C. 23°C is room temperature. 200°C of the second measurement temperature T2 is a temperature that can occur as an environment in which automobile motors and industrial motors operate.20 [0097] First, the residual magnetic flux density and the coercive force in each sample according to Examples 1 to 8 and Comparative Examples 2 to 12 are determined in comparison with Comparative Example 1. When the values of the residual magnetic flux density and the coercive force of each sample25 at 23°C are within an allowable measurement error of 1% compared with the values of Comparative Example 1, the values are rated as “equivalent”. Values of 1% or more higher are rated as “good”, and values of 1% or more lower are rated as “poor”.30 [0098] Next, the temperature coefficient α of residual magnetic flux density is calculated using the residual magnetic flux density at the first measurement temperature 44 T1 of 23°C and the residual magnetic flux density at the second measurement temperature T2 of 200°C. The temperature coefficient β of coercive force is calculated using the coercive force at the first measurement temperature T1 of 23°C and the coercive force at the second measurement5 temperature T2 of 200°C. The temperature coefficient of residual magnetic flux density and the temperature coefficient of coercive force in each sample according to Examples 1 to 8 and Comparative Examples 2 to 12 are determined in comparison with Comparative Example 1. When10 the values of each sample are within an allowable measurement error of ±1% compared with the absolute value |α| of the temperature coefficient of residual magnetic flux density and the absolute value |β| of the temperature coefficient of coercive force in the sample of Comparative Example 1, the15 values are rated as “equivalent”. Values of −1% or more lower are rated as “good”, and values of +1% or more higher are rated as “poor”. Because the samples determined to be “good” have a smaller temperature coefficient, it is possible to provide the rare earth sintered magnet 1 having stable20 magnetic properties even in a high temperature environment while preventing degradation of magnetic properties associated with temperature rise. [0099] Next, regarding the magnetizing ability, the magnetization rate is calculated from the ratio of the25 magnetic flux density, which is one intersection of the magnetic hysteresis of the applied magnetic field of 20kOe and the permeance coefficient Pc, and the magnetic flux density, which is one intersection of the magnetic hysteresis of the applied magnetic field of 80kOe in the saturation30 magnetization state and the permeance coefficient Pc. The magnetizing ability in each sample according to Examples 1 to 8 and Comparative Examples 2 to 12 is determined in 45 comparison with Comparative Example 1. That is, for each sample, compared with the magnetization rate in the sample according to Comparative Example 1, values of −1% or more higher, being considered as a measurement error, are rated as “equivalent or better”, and values of −1% or more lower5 are rated as “poor”. It is possible to provide the rare earth sintered magnet 1 having high magnetizing ability for samples rated as “equivalent or better”. [0100] The results of determination of the residual magnetic flux density, the coercive force, the temperature10 coefficient of residual magnetic flux density, the temperature coefficient of coercive force, and the magnetizing ability are shown in Table 3. [0101] Comparative Example 1 is a sample of the rare earth sintered magnet 1 prepared in the form of Nd-Fe-B with the15 production method described in Patent Literature 1 using Nd, Fe, and FeB as raw materials. From the observation of the structure form of this sample with the method described above, due to the absence of Pr, La, and Sm, no core-shell structure is confirmed in the main phase 10, and it is not confirmed20 that the concentration of Sm in the subphase 20 is higher in the first subphase 21 than in the second subphase 22. The evaluation of the magnetic properties of this sample with the method described above shows that the residual magnetic flux density is 1.3 T and the coercive force is 1000 kA/m.25 The temperature coefficients of residual magnetic flux density and coercive force are |α|=0.191 %/°C and |β|=0.460 %/°C, respectively. The magnetization rate is 98.6%. These values of Comparative Example 1 are used as a reference.30 [0102] Comparative Example 2 is a sample of the rare earth sintered magnet 1 prepared in the form of (Nd, Dy)-Fe-B with the production method described in Patent Literature 1 using 46 Nd, Dy, Fe, and FeB as raw materials. From the observation of the structure form of this sample with the method described above, due to the absence of Pr, La, and Sm, no core-shell structure is confirmed in the main phase 10, and it is not confirmed that the concentration of Sm in the5 subphase 20 is higher in the first subphase 21 than in the second subphase 22. The evaluation of the magnetic properties of this sample with the method described above shows that the residual magnetic flux density is “poor”, the coercive force is “good”, the temperature coefficient of10 residual magnetic flux density is “equivalent”, the temperature coefficient of coercive force is “equivalent”, and the magnetizing ability is “equivalent or better”. This result reflects the fact that the coercive force is improved by substituting Dy having high magnetocrystalline anisotropy15 for a part of Nd. [0103] Comparative Example 3 is a sample of the rare earth sintered magnet 1 prepared in the form of (Nd, Pr)-Fe-B with the production method described in Patent Literature 1 using Nd, Pr, Fe, and FeB as raw materials. From the observation20 of the structure form of this sample with the method described above, the main phase 10 in which Nd and Pr are provided mixedly is confirmed due to the addition of Pr, but a core-shell structure is not formed. In addition, due to the absence of La and Sm, it is also not confirmed that the25 concentration of Sm in the subphase 20 is higher in the first subphase 21 than in the second subphase 22. The evaluation of the magnetic properties of this sample with the method described above shows that the residual magnetic flux density is “equivalent”, the coercive force is “good”, the30 temperature coefficient of residual magnetic flux density is “equivalent”, the temperature coefficient of coercive force is “poor”, and the magnetizing ability is “equivalent or 47 better”. This result reflects the fact that the magnetic anisotropy of the main phase 10 is increased and the coercive force is improved by the addition of Pr, but the structure form is not optimal in the main phase 10 and the subphase 20.5 [0104] Comparative Example 4 is a sample of the rare earth sintered magnet 1 prepared in the form of (Nd, La, Sm)-Fe-B with the production method described in Patent Literature 1 using Nd, La, Sm, Fe, and FeB as raw materials. From the observation of the structure form of this sample with the10 method described above, no core-shell structure is confirmed in the main phase 10 due to the absence of Pr. In addition, due to the addition of La and Sm, the concentration of Sm is segregated in one subphase 20 along with the segregation of La, but the second subphase 22 does not exist. Furthermore,15 it is also not confirmed that the concentration of Sm is higher in the first subphase 21 than in the second subphase 22. The evaluation of the magnetic properties of this sample with the method described above shows that the residual magnetic flux density is “equivalent”, the coercive force is20 “equivalent”, the temperature coefficient of residual magnetic flux density is “good”, the temperature coefficient of coercive force is “good”, and the magnetizing ability is “equivalent or better”. This result reflects the fact that the presence of La and Sm in the main phase 10 or the subphase25 20 gives a good result in the temperature coefficient of the magnetic properties, but the magnetic properties at room temperature are not improved, and the structure form is not optimal in the main phase 10 and the subphase 20. [0105] Comparative Example 5 is a sample of the rare earth30 sintered magnet 1 prepared in the form of (Nd, La, Sm)-Fe-B with the production method described in Patent Literature 1 using Nd, La, Sm, Fe, and FeB as raw materials. The 48 composition ratio of Nd, La, and Sm is different from that of Comparative Example 4. From the observation of the structure form of this sample with the method described above, no core-shell structure is confirmed in the main phase 10 due to the absence of Pr. In addition, due to the addition5 of La and Sm, the concentration of Sm is segregated in one subphase 20 along with the segregation of La, but the second subphase 22 does not exist. Furthermore, it is also not confirmed that the concentration of Sm is higher in the first subphase 21 than in the second subphase 22. The evaluation10 of the magnetic properties of this sample with the method described above shows that the residual magnetic flux density is “equivalent”, the coercive force is “equivalent”, the temperature coefficient of residual magnetic flux density is “good”, the temperature coefficient of coercive force is15 “good”, and the magnetizing ability is “equivalent or better”. This result reflects the fact that the presence of La and Sm in the main phase 10 or the subphase 20 gives a good result in the temperature coefficient of the magnetic properties, but the magnetic properties at room temperature are not20 improved, and the structure form is not optimal in the main phase 10 and the subphase 20: the change in the composition ratio of Nd, La, Sm results in almost the same result as in Comparative Example 4. [0106] Comparative Example 6 is a sample of the rare earth25 sintered magnet 1 prepared in the form of (Nd, Pr, La, Sm)- Fe-B with the production method described in Patent Literature 1 using Nd, Pr, La, Sm, Fe, and FeB as raw materials. From the observation of the structure form of this sample with the method described above, the main phase30 10 in which Nd and Pr are provided mixedly is confirmed due to the addition of Pr, but a core-shell structure is not formed. In addition, due to the addition of La and Sm, the 49 concentration of Sm is segregated in one subphase 20 along with the segregation of La, but the second subphase 22 does not exist. Furthermore, it is also not confirmed that the concentration of Sm is higher in the first subphase 21 than in the second subphase 22. The evaluation of the magnetic5 properties of this sample with the method described above shows that the residual magnetic flux density is “equivalent”, the coercive force is “good”, the temperature coefficient of residual magnetic flux density is “good”, the temperature coefficient of coercive force is “equivalent”, and the10 magnetizing ability is “equivalent or better”. This result reflects the fact that that the addition of Pr increases the magnetic anisotropy of the main phase 10 to improve the coercive force, and the presence of La and Sm in the main phase 10 or the subphase 20 improves the temperature15 coefficient of the magnetic properties, particularly the temperature coefficient of the coercive force, but the structure form is not optimal in the main phase 10 and the subphase 20. [0107] Comparative Example 7 is a sample of the rare earth20 sintered magnet 1 prepared in the form of Nd-Fe-B with the production method including the hot working method described in Patent Literature 2 using Nd, Fe, and FeB as raw materials. From the observation of the structure form of this sample with the method described above, due to the absence of Pr,25 La, and Sm, no core-shell structure is confirmed in the main phase 10, and it is not confirmed that the concentration of Sm in the subphase 20 is higher in the first subphase 21 than in the second subphase 22. However, the refinement of the structure, which is a characteristic of a magnet produced30 with the hot working method, is confirmed. The evaluation of the magnetic properties of this sample with the method described above shows that the residual magnetic flux density 50 is “poor”, the coercive force is “good”, the temperature coefficient of residual magnetic flux density is “equivalent”, the temperature coefficient of coercive force is “equivalent”, and the magnetizing ability is “poor”. This result reflects the decrease in residual magnetic flux5 density and deterioration in magnetizing ability despite the improvement of the coercive force associated with the refinement of the structure through the hot working method. [0108] Comparative Example 8 is a sample of the rare earth sintered magnet 1 prepared in the form of (Nd, Dy)-Fe-B with10 the production method including the hot working method described in Patent Literature 2 using Nd, Dy, Fe, and FeB as raw materials. From the observation of the structure form of this sample with the method described above, due to the absence of Pr, La, and Sm, no core-shell structure is15 confirmed in the main phase 10, and it is not confirmed that the concentration of Sm in the subphase 20 is higher in the first subphase 21 than in the second subphase 22. The evaluation of the magnetic properties of this sample with the method described above shows that the residual magnetic20 flux density is “poor”, the coercive force is “good”, the temperature coefficient of residual magnetic flux density is “equivalent”, the temperature coefficient of coercive force is “equivalent”, and the magnetizing ability is “poor”. This indicates that the coercive force is significantly improved25 by the substitution of Dy having high magnetocrystalline anisotropy for a part of Nd in addition to the manufacture with hot working, but the other properties reflect the structure refinement. [0109] Comparative Example 9 is a sample of the rare earth30 sintered magnet 1 prepared in the form of (Nd, Pr)-Fe-B with the production method including the hot working method described in Patent Literature 2 using Nd, Pr, Fe, and FeB 51 as raw materials. From the observation of the structure form of this sample with the method described above, the core-shell structure is confirmed through hot working in addition to the addition of Pr, but there is only one type of main phase 10 having a high Pr concentration in the core5 portion. In addition, due to the absence of La and Sm, it is also not confirmed that the concentration of Sm in the subphase 20 is higher in the first subphase 21 than in the second subphase 22. The evaluation of the magnetic properties of this sample with the method described above10 shows that the residual magnetic flux density is “poor”, the coercive force is “good”, the temperature coefficient of residual magnetic flux density is “equivalent”, the temperature coefficient of coercive force is “equivalent”, and the magnetizing ability is “poor”. This indicates that15 the coercive force is significantly improved to the level of the rare earth sintered magnet 1 containing Dy due to the formation of the core-shell structure having a high Pr concentration in the core portion, but the other properties reflect the structure refinement.20 [0110] Comparative Example 10 is a sample of the rare earth sintered magnet 1 prepared in the form of (Nd, La, Sm)-Fe-B with the production method including the hot working method described in Patent Literature 2 using Nd, La, Sm, Fe, and FeB as raw materials. From the observation of the25 structure form of this sample with the method described above, no core-shell structure is confirmed in the main phase 10 due to the absence of Pr. In addition, due to the addition of La and Sm, the concentration of Sm is segregated in one subphase 20 along with the segregation of La, but the second30 subphase 22 does not exist. Furthermore, it is also not confirmed that the concentration of Sm is higher in the first subphase 21 than in the second subphase 22. The evaluation 52 of the magnetic properties of this sample with the method described above shows that the residual magnetic flux density is “poor”, the coercive force is “good”, the temperature coefficient of residual magnetic flux density is “good”, the temperature coefficient of coercive force is “good”, and the5 magnetizing ability is “poor”. This result reflects the fact that the presence of La and Sm in the main phase 10 or the subphase 20 gives a good result in the temperature coefficient of the magnetic properties, but the residual magnetic flux density and the magnetizing ability at room10 temperature are not improved, and the structure form is not optimal in the main phase 10 and the subphase 20. [0111] Comparative Example 11 is a sample of the rare earth sintered magnet 1 prepared in the form of (Nd, La, Sm)-Fe-B with the production method including the hot working15 method described in Patent Literature 2 using Nd, La, Sm, Fe, and FeB as raw materials. The composition ratio of Nd, La, and Sm is different from that of Comparative Example 10. From the observation of the structure form of this sample with the method described above, no core-shell structure is20 confirmed in the main phase 10 due to the absence of Pr. In addition, due to the addition of La and Sm, the concentration of Sm is segregated in one subphase 20 along with the segregation of La, but the second subphase 22 does not exist. Furthermore, it is also not confirmed that the concentration25 of Sm is higher in the first subphase 21 than in the second subphase 22. The evaluation of the magnetic properties of this sample with the method described above shows that the residual magnetic flux density is “poor”, the coercive force is “good”, the temperature coefficient of residual magnetic30 flux density is “good”, the temperature coefficient of coercive force is “good”, and the magnetizing ability is “poor”. This result reflects the fact that the presence of 53 La and Sm in the main phase 10 or the subphase 20 gives a good result in the temperature coefficient of the magnetic properties, but the residual magnetic flux density and the magnetizing ability at room temperature are not improved, and the structure form is not optimal in the main phase 105 and the subphase 20. The change in the composition ratio of Nd, La, Sm results in almost the same result as in Comparative Example 10. [0112] Comparative Example 12 is a sample of the rare earth sintered magnet 1 prepared in the form of (Nd, Pr, La,10 Sm)-Fe-B with the production method including the hot working method described in Patent Literature 2 using Nd, Pr, La, Sm, Fe, and FeB as raw materials. From the observation of the structure form of this sample with the method described above, the core-shell structure is confirmed through hot15 working in addition to the addition of Pr, but there is only one type of main phase 10 having a high Pr concentration in the core portion. In addition, due to the addition of La and Sm, the concentration of Sm is segregated in one subphase 20 along with the segregation of La, but the second subphase20 22 does not exist. Furthermore, it is also not confirmed that the concentration of Sm is higher in the first subphase 21 than in the second subphase 22. The evaluation of the magnetic properties of this sample with the method described above shows that the residual magnetic flux density is “poor”,25 the coercive force is “good”, the temperature coefficient of residual magnetic flux density is “good”, the temperature coefficient of coercive force is “good”, and the magnetizing ability is “poor”. This indicates that the coercive force is significantly improved to the level of the rare earth30 sintered magnet 1 containing Dy due to the formation of the core-shell structure having a high Pr concentration in the core portion, and the presence of La and Sm in the main phase 54 10 or the subphase 20 improves the temperature coefficient of the magnetic properties, particularly the temperature coefficient of the coercive force. However, the result also reflects the fact that the residual magnetic flux density and the magnetizing ability at room temperature are not5 improved, and the structure form is not optimal in the main phase 10 and the subphase 20. [0113] The samples of Examples 1 to 8 are the rare earth sintered magnet 1 including the main phase 10 that satisfies a general formula (Nd, Pr, R)-Fe-B, where R is one or more10 rare earth elements selected excluding Nd and Pr, the main phase 10 containing crystal grains based on an Nd2Fe14B crystal structure, wherein the main phase 10 includes a core portion and a shell portion covering the core portion, the main phase 10 includes the first main phase 11 that satisfies15 CNd>CPr and the second main phase 12 that satisfies CNdCPr and a second main phase that satisfies10 CNdC2Nd and C1PrSNd and CPrSPr, where SNd is concentration of Nd in the shell portion and 57 SPr is concentration of Pr in the shell portion. [Claim 5] The rare earth sintered magnet according to claim 1, further comprising, given R=La and/or Sm, a first subphase that is crystalline and has a main component based on an5 oxide phase represented by (Nd, Pr, La, Sm)-O, and a second subphase that is crystalline and has a main component represented by (Nd, Pr, La)-O, wherein concentration of Sm is higher in the first subphase than in the second subphase.10 [Claim 6] The rare earth sintered magnet according to claim 5, wherein 1<(Y1+Y2)/Y<(X1+X2)/X is satisfied, where X represents concentration of La contained in the main phase, X1 represents concentration of La contained in the first15 subphase, X2 represents concentration of La contained in the second subphase, Y represents concentration of Sm contained in the main phase, Y1 represents concentration of Sm contained in the first subphase, and Y2 represents concentration of Sm contained in the second subphase.20 [Claim 7] The rare earth sintered magnet according to claim 4, wherein concentrations of Nd and Pr contained in the first main phase satisfy a relational expression of (CNd+SNd)>(X+Y),25 and concentrations of Nd and Pr contained in the second main phase satisfy a relational expression of (CPr+SPr)>(X+Y). 30 [Claim 8] A method for producing the rare earth sintered magnet according to any one of claims 1 to 7, the method comprising: 58 a melting step of melting a raw material of a rare earth sintered magnet alloy containing an element constituting the rare earth sintered magnet; a primary cooling step of cooling the raw material molten in the melting step to obtain a solidified alloy;5 a secondary cooling step of further cooling the solidified alloy to obtain a rare earth sintered magnet alloy; a pulverizing step of pulverizing the rare earth sintered magnet alloy satisfying (Nd, Pr, R)-Fe-B;10 a molding step of preparing a molded body by molding powder of the rare earth sintered magnet alloy pulverized in the pulverizing step; a sintering step of obtaining a sintered body by sintering the molded body at a sintering temperature that is15 a predetermined temperature; a primary aging step of holding the sintered body at a primary aging temperature that is a temperature lower than the sintering temperature; a secondary aging step of holding the sintered body20 held in the primary aging step at a secondary aging temperature that is a temperature lower than the primary aging temperature; a tertiary aging step of holding the sintered body held in the secondary aging step again at the primary aging25 temperature; a quaternary aging step of holding the sintered body held in the tertiary aging step again at the secondary aging temperature; and a cooling step of cooling the sintered body held in the30 quaternary aging step. 59 [Claim 9] A rotor comprising: a rotor core; and the rare earth sintered magnet according to any one of claims 1 to 7 provided in the rotor core. 5 [Claim 10] A rotary machine comprising: the rotor according to claim 9; and an annular stator facing the rotor and including, on an inner surface on a side where the rotor is placed, windings provided on teeth protruding toward the rotor.10