Rare earth metal-free hard magnets

Abstract

To provide a hard magnetic material which does not contain rare earth metals but simultaneously exhibits high coercivity, high residual magnetism and high energy density.SOLUTION: An intermetallic compound has the following general composition of XaX'bYcZd. In the formula, X and X' are each independently a 3d transition metal with an unpaired electron, Y is a 4d or 5d transition metal of group 5, 8, 9 or 10, Z is a typical element of group 13, 14 or 15, a and d are each independently a number between 0.1 and 2.0, and b and c are each independently a number between 0.0 and 2.0, provided that a+b+c+d is between 3.0 and 4.0.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to materials that include permanent magnetic properties, also known as hard magnets. A good hard magnet or permanent magnet should generate a high magnetic field, withstand external forces that demagnetize it, and be mechanically tough.

Background Art

[0002] Permanent magnetic materials play an important role in many areas of life, such as medical diagnosis, magnetic circuits, and spintronics.

[0003] Typically, hard magnetic materials are ferromagnetic materials characterized by high remanence and high saturation coercivity.

[0004] When a ferromagnetic material is magnetized in one direction, it will not relax to zero magnetization even if the applied magnetic field is removed. The amount of magnetization that it retains at zero applied magnetic field is called remanence. To reverse the magnetization back to zero, a magnetic field in the opposite direction must be applied, and the amount of the opposite magnetic field required for demagnetization is called saturation coercivity. When an alternating magnetic field is applied to the material, its magnetization will follow a loop called a hysteresis loop. This hysteresis phenomenon is related to the existence of magnetic domains ("Weiss domains"). Some ferromagnetic materials will retain the applied magnetization almost indefinitely and are therefore useful as "permanent magnets".

[0005] To be considered a potential permanent magnet, three intrinsic properties of the magnetic material: - The Curie temperature (T C ), above which the cooperative magnetic action of the ferromagnetic or ferrimagnetic material disappears, - The saturation magnetization (Ms), which is crucial for the energy density (BH) max , and - The uniaxial crystalline magnetic anisotropy, usually represented by the anisotropy magnetic field B a , which represents the upper limit of the potential coercivity of the permanent magnet. is particularly important.

[0006] Currently, the most widely used high-performance permanent magnets are samarium and cobalt (Sm-Co), as well as neodymium, iron and boron (Nd-Fe-B, e.g., Nd2Fe 14 B) rare earth metal compounds. The latter has a coercivity of about 1.2 T, a residual magnetism of about 1.2 T, and a maximum energy density (BH) max of about 400 kJ / m -3 However, in order to improve corrosion stability and intrinsic coercivity, dysprosium or praseodymium is required. These rare earth elements are "strategic materials" due to their limited resources. Their availability is easily subject to political constraints. Moreover, due to the sensitivity of these materials to corrosion, their use temperature is limited to less than 200 °C.

[0007] Due to the magnetic properties of rare earth permanent magnets, they are superior to all known systems so far, and there is no actual commercial alternative to strong rare earth permanent magnets yet. Rare earth permanent magnets have high magnetic anisotropy because the electrons in the f-shell are shielded from the ligand field, and thus the orbital angular momentum of the shell shows its advantages. In addition, they can exhibit a high local magnetic moment, enabling even higher saturation magnetization.

[0008] An alternative to rare earth metals is ferrite, which is manufactured on a large scale and typically has an energy density (BH) max less than 40 kJ / m -3 The use of ferrite is limited to applications with low energy density, low cost, and a maximum use temperature of 250 °C.

[0009] A further alternative is alnico magnets, which have a (BH) max of about 80 kJ / m -3 The relatively high (BH) for rare earth metal-free alloys max is due to a high residual magnetism of about 1.1 T. Moreover, a coercive force of about 0.14 T, μ0H CThe magnetic field strength is relatively low, meaning that Alnico magnets are at risk of irreversible loss even at low magnetic field strengths. In addition, the bulk material is very brittle and therefore mechanically fragile. However, their high operating temperature of up to 550°C is a considerable advantage.

[0010] MnAl-based magnets currently have a Curie temperature of approximately 280°C (BH) max Approximately 60kJm -3 It has reached [a certain value]. Their residual magnetism and saturation coercivity are [a certain value]. r Approximately 0.6T and μ0H C It is equivalent to approximately 0.4T. They do not contain "important" elements and are therefore relatively inexpensive. Moreover, their density is approximately 5 gcm³. -3 While they are relatively lightweight, their coercivity of 0.5T or less is quite low.

[0011] (BH) max Approximately 50kJm -3 Bulk magnets and thin-film magnets having the following properties can also be manufactured from MnBi. The hard magnetic properties of MnBi are based on the uniaxial symmetry of its hexagonal crystal structure, its out-of-plane magnetization, and the strong spin-orbit coupling of heavy Bi.

[0012] Binary compounds that crystallize in a tetragonal crystal structure of type L10, such as CoPt or FePt, can exhibit a coercivity of 2T. However, high platinum content is economically disadvantageous.

[0013] Furthermore, some Heusler compounds are known to possess hard magnetic properties. Heusler compounds are ternary intermetallic compounds of the formula X²YZ or XYZ [wherein X and Y are usually transition metals and Z is a main group element], the latter also known as semi-Heusler compounds. The class of Heusler alloys includes more than 1000 compounds that can be ferromagnetic or ferrimagnetic, although the elements that make up the compounds do not necessarily possess these magnetic properties. Members of the tetragonal family of Heusler compounds can exhibit high crystalline magnetic anisotropy due to their inherent uniaxial symmetry. Since tetragonal compounds are usually ferrimagnetic, they exhibit only low saturation magnetization and, therefore, low remanence.

[0014] In addition to further development and improvement of rare earth permanent magnets, (BH) max 100-300 kJm -3 Research into new systems that bridge the gap between ferrite and Nd-Fe-B, which falls within this range, represents an important step for future technologies. [Overview of the Initiative] [Problems that the invention aims to solve]

[0015] Therefore, the object of the present invention is to provide a hard magnetic material that does not contain rare earth metals but simultaneously exhibits high saturation coercivity, high remanence, and high energy density (compared to known hard magnets containing non-rare earth metals). [Means for solving the problem]

[0016] The above problem concerns general composition X a X' b Y c Z d [In the formula, X and X' represent 3d transition metals with high total spin, i.e., unpaired electrons, such as Mn, Fe, Co, and Ni; Y is a 4d or 5d transition metal of group 5, 8, 9, or 10, characterized by high spin-orbit coupling (SOC), such as Ru, Rh, Pd, Pt, Ir, Ag, Au, Nb, or Ta; Z is a typical element of groups 13, 14, or 15, such as Al, Ga, In, Ge, Sn. These are As, Sb, or Bi, and among these elements, the higher-period homologs (In, Sn, Sb, or Bi) are also characterized by high spin-orbit coupling (SOC); a and d represent numbers between 0.1 and 2.0; b and c represent numbers between 0.0 and 2.0; [a+b+c+d is assumed to be between 3.0 and 4.0] This is resolved by rare-earth metal-free ternary intermetallic compounds having hexagonal or trigonal symmetry.

[0017] Therefore, in total, X a X' b Y c Z d This represents an intermetallic compound whose composition lies between that of a Heusler compound and a semi-Heusler compound.

[0018] These novel compounds are characterized by high uniaxial crystalline magnetic anisotropy, and therefore, they are suitable for the production of rare-earth-free permanent magnetic materials with high coelectric fields. [Brief explanation of the drawing]

[0019] [Figure 1] This figure shows room-temperature powder X-ray diffraction patterns of a 22 nm thin Mn1.5PtGa layer and a 44 nm thin Mn1.08Fe0.58Pt1.19Ga layer grown on the (001) surface of a sapphire support (Al2O3) at different temperatures: a) 200°C; b) 300°C; c) 400°C; d) 300°C. [Figure 2]The figures show: a) the temperature dependence of magnetization at cooling and 0.05T for a thin layer of Mn1.5PtGa on a sapphire substrate (001) during cooling; b) out-of-plane (OP) and in-plane (IP) hysteresis curves at 20K; c) out-of-plane (OP) and in-plane (IP) hysteresis curves at 200K; and d) out-of-plane hysteresis curves for a 22nm thin Mn1.5PtGa layer deposited on a sapphire substrate at various temperatures (20, 50, 100, 150, and 200K). [Figure 3] This figure shows a) the temperature dependence of magnetization in an external magnetic field of 0.1 T at cooling and a thin layer of Mn1.08Fe0.58Pt1.19Ga with a thickness of 44 nm coated on a sapphire (001) carrier at 300°C; and b) the out-of-plane (OP) hysteresis curves at 50K and 300K. [Modes for carrying out the invention]

[0020] The ternary intermetallic compounds according to the present invention have a hexagonal or trigonal structure. This symmetrical crystal structure is an important feature because it satisfies the criterion of crystal anisotropy due to its inherent uniaxial symmetry. In the compounds of the present invention, this crystal anisotropy is combined with explicit spin-orbit coupling of 4d and 5d elements (transition metals or main group elements). As a result, these compounds exhibit strong magnetic anisotropy due to crystal magnetic anisotropy, even in the absence of shape anisotropy.

[0021] The intermetallic compound of the present invention has a general composition X a X' b Y c Z d It has the characteristic of being, and therefore, compositionally, it is located between Heusler compounds and semi-Heusler compounds.

[0022] Heusler compounds are intermetallic compounds with a general composition of X2YZ, and crystallize in the L21 structural type (Pearson's Handbook of Crystallographic Data for Intermetallic Phases, ASM). International,The Materials Information Society, 1991). Intermetallic compounds are generally, a) Between two or more true metals (T1 and T2) b) Between one or more true metals and one or more true metals of subgroup B c) Between two or more metals of subgroup B It is a compound of [the compound].

[0023] The properties of these compounds, as we move from a) to c), become less metallic and increasingly similar to those of actual compounds. The classification into true metals and elements of subgroup B is explained by Walter C.E. Vans (Introduction to Crystal Chemistry). Adopted from Table 13.1 (from de Gruyter Verlag Berlin New York 1976, p. 276).

[0024] [Table 1]

[0025] The lanthanide and actinide metals belong to class T2. In Heusler compounds X2YZ, X and Y are mainly transition metal elements (T2 in the table above), and sometimes Y is a rare earth element. Z is a non-magnetic metal or nonmetal (B1 or B2).

[0026] The intermetallic compound of the present invention has a general composition X a X' b Y c Z d These have the following properties. In each of these Heusler compounds and semi-Heusler compounds, X and X' represent 3d transition metals with high total spin, i.e., unpaired electrons, preferably Mn, Fe, Co, or Ni; Y is a 4d or 5d transition metal of group 5, 8, 9, or 10, preferably Ru, Rh, Pd, Pt, Ir, Ag, Au, Nb, or Ta, whose metal is characterized by high spin-orbit coupling (SOC); Z is a typical element of group 13, 14, or 15, preferably Al, Ga, In, Ge, Sn, As, Sb, or Bi, and among these elements, the higher period congeners (In, Sn, Sb, or Bi) are also characterized by high spin-orbit coupling (SOC); a and d represent numbers between 0.1 and 2.0; b and c represent numbers between 0.0 and 2.0; However, a+b+c+d must be between 3.0 and 4.0.

[0027] In the Heusler compound of the present invention, parameters a, b, c, and d can be independently selected from numbers between 0.1 and 2.0 (with respect to a and d) and numbers between 0.0 and 2.0 (with respect to b and c). Preferably, a is 1 or 2, more preferably a is 1 when b is 1, and a is 2 when b is 0. Preferably d is 1. Preferably b is 0, or preferably b is 1 when a is 1. Preferably c is 1.

[0028] Generally, the sum of a, b, c, and d is between 3.0 and 4.0, preferably 3.0 or 4.0.

[0029] Manufacturing method For the production of the compound of the present invention, sputtering technology is used. This enables the production of a thin layer (thin film) of the compound. For this purpose, elemental metals and / or alloys of two metals are used as targets in sputtering. The base pressure of the vacuum receiver is preferably 10 -6 mbar or less, civilization 10 -7 mbar or less, most preferably 10 -8 The volume is less than mbar, and the sediment is 0.1 × 10⁻⁶. -3 mbar~10×10 -3mbar, fuwa1×10 -3 mbar~5×10 -3 mbar, most preferably 3 × 10 -3 The process is preferably carried out in mbar at a preferred temperature range of 100°C to 500°C, more preferably 150°C to 450°C, and most preferably 200°C to 400°C. The growth rate of the thin layer is about 0.03 to 0.04 nm / s. After deposition, the thin layer on the substrate in the recipient is preferably vacuum annealed for 5 to 25 minutes, more preferably 10 to 20 minutes, and most preferably about 15 minutes, and then slowly cooled to room temperature. Next, a protective layer of aluminum, preferably 2 to 3 nm thick, is deposited to pre-coat the thin metal layer and protect it from oxidation.

[0030] By changing the deposition parameters, the crystal structure of the deposited material can be influenced. At low deposition temperatures of approximately 200°C, hexagonal structures are preferentially formed, while it has been found that increasing the temperature (to approximately 400°C) increases the proportion of tetragonal semi-Heusler compounds. In a more preferred embodiment, the compounds can be obtained by epitaxial growth of thin films on a predetermined substrate having a desired crystal structure, such as a sapphire substrate (along the 0001 direction) or on MgO (along the 001 direction) as the substrate. The hexagonal compounds of the present invention have been observed to grow preferentially on sapphire, with the crystallographic

[0001] direction perpendicular to the substrate surface. In principle, hexagonal Ru or Co can also be used as substrate surfaces. However, these substrates have higher lattice mismatch compared to the hexagonal compounds of the present invention and are therefore less preferred. Further, but still less preferred, options are hexagonal SiC(2H) and trigonal SiO2 as substrates, and thin layers grown on these types of substrates showed less crystallinity.

[0031] Manufacturing of magnets for use For use as magnets, the compounds of the present invention can be, for example, sintered as raw materials or bonded with a suitable binder material. Sintered magnets are usually strong and anisotropic, but their shape is limited. They are made by a compression molding of the raw materials followed by a heating process. Bonded magnets are not as strong as sintered ones, but are not as expensive and can be made in almost any size and shape. With respect to bonded magnets, the raw materials (compounds according to the present invention) are mixed with 5 to 90% by weight, preferably 10 to 60% by weight, more preferably 20 to 40% by weight of a binder, compressed, and cured at a high temperature (for example, 50 to 350°C, preferably 80 to 280°C, more preferably 100 to 200°C, depending on the temperature stability of the binder and magnetic compound used). They are isotropic, that is, they can be magnetized in any direction. The molding process may be, for example, injection molding or a compression bonding process. Typical binder types include nylon, polyamide, polyphenylene sulfide (PPS), and nitrile butadiene rubber (NBR). [Examples]

[0032] Apparatus and measurement methods The crystal structure and film thickness are determined by CuK α The samples were tested using X-ray diffraction (XRD) measurements (Philips PANanalytical X'pert Pro) with a specific source. To determine the composition of the film, energy-dispersive X-ray spectroscopy (EDX) measurements were performed using QUANTA. The experiment was conducted using 200 FEG I. Film thickness was obtained using the StrataGEM software package. The magnetic properties of the thin film were studied using a Quantum Design superconducting quantum interference device vibrational sample magnetometer (MPMS-3).

[0033] Examples 1 and 2 Mn 1.5 PtGa and Mn 1.08 Fe 0.58 Pt 1.19 Ga Mn 1.5 PtGa and Mn1.08 Fe 0.58 Pt 1.19 A thin layer of Ga was fabricated by epitaxial growth on a sapphire surface (0001) as a substrate. Since sapphire (Al2O3) crystallizes in a trigonal crystal system, i.e., with a hexagonal metric, the structure of the sapphire surface is Mn 1.5 PtGa and Mn 1.08 Fe 0.58 Pt 1.19 This supports epitaxial growth of the Ga layer.

[0034] The elements manganese, platinum, iron, and alloys with the composition MnGa were used as sputtering targets. The base pressure of the vacuum receiver was 10 -8 The amount of deposit on the substrate is less than mbar, and the amount is 3 × 10⁻¹⁶ mbar. -3 The deposition was carried out in mbar at a temperature range of 200°C to 300°C. The growth rate of the thin layer was approximately 0.03 to 0.04 nm / s. After deposition, the thin layer on the substrate in the recipient was vacuum annealed for 15 minutes and then slowly cooled to room temperature. Next, a 2-3 nm aluminum protective layer was deposited to protect the thin metal layer from oxidation.

[0035] Mn 1.5 22nm thin layer of PtGa and Mn 1.08 Fe 0.58 Pt 1.19Figure 1 shows powder X-ray diffraction patterns at room temperature in the "out-of-plane" geometry for a 44 nm thin layer of Ga. Bragg reflections of the hexagonal structure are labeled H(0002) and H(0004). The thin layer grown at 300°C (Figure 1b) shows better crystallinity compared to the layer coated at 200°C (Figure 1a). At deposition temperatures above 300°C (Figure 1c), a decrease in Bragg intensity and additional weak reflections (marked with *) were observed. The additional reflections can be attributed to the tetragonal semi-Heusler compound as a second phase. Similar behavior was observed in bulk samples. Even with partial substitution of Mn by Fe, the hexagonal structure is maintained, as shown in Figure 1d. All thin films deposited on sapphire (0001) exhibit texture regardless of the deposition temperature. Epitaxial growth on the surface of a trigonal substrate results in the formation of hexagonal Mn 1.5 PtGa and Mn 1.08 Fe 0.58 Pt 1.19 Each layer of Ga was deposited with a preferred orientation in the crystallographic

[0001] direction, perpendicular to the surface of the substrate and therefore parallel to the crystallographic c-axis of sapphire.

[0036] The crystal structure of deposited material can be influenced by different deposition parameters. At low deposition temperatures, hexagonal structures preferentially form, while the proportion of tetragonal semi-Heusler compounds increases with increasing temperature. The lattice parameters of the hexagonal structure are Mn 1.5 For PtGa, a=4.35Å and c=5.58Å, Mn 1.08 Fe 0.58 Pt 1.19 For Ga, a=4.33Å and c=5.52Å. This corresponds to a lattice mismatch of approximately 8.2% and 8.6% in the a-axis, compared to a=4.74Å in the a-axis of the sapphire substrate. Despite the relatively large lattice mismatch, the Mn at the sapphire surface (0001) of the substrate... 1.5 PtGa and Mn 1.08 Fe 0.58 Pt 1.19 Epitaxial growth of Ga was observed.

[0037] Mn deposited on the sapphire (0001) surface at 300 °C 1.5 The magnetic properties of the well-crystalline thin layer of PtGa are shown in Fig. 2. Fig. 2a shows the magnetization measured in the field-cooled mode (FC) at a magnetic field strength of 0.05 T as a function of temperature. At a Curie temperature (T C ) of about 241 K, a ferromagnetic to paramagnetic phase transition was observed. The corresponding M(H) curves for 20 K and 200 K are shown in Figs. 2b and 2c, respectively, with respect to the "in-plane" (IP) and "out-of-plane" (OP) directions. The data shown correspond to the raw data after subtracting the contribution of the substrate for each temperature. The sample shows a coercive field strength Hc of 1.5 T at 20 K in the "out-of-plane" orientation, but at 200 K it shows only a saturation remanence (0.18 T) that almost disappears (due to the temperature dependence of magnetic anisotropy). Fig. 2d shows the systematic decrease in the saturation remanence with increasing temperature. The measured values of the coercive force in the "out-of-plane" direction show strong magnetic anisotropy compared to the "in-plane" measurement. At 20 K and 5 T, a total magnetization of 400 kA / m was measured. This results in an anisotropy constant (K U =(μ0M S ×H a ) / 2 of 3.3 MJ / m U 3.3 MJ / m 3 . M S is the saturation magnetization and Ha is the anisotropy magnetic field. The estimated value of the latter is obtained by using the intersection of the "in-plane" and "out-of-plane" plots. The thin layer of Mn 1.5 PtGa showed a (BH) max of about 30 kJm -3 at 20 K. As the temperature increases, (BH) max decreases, and at 200 K, i.e., near the Curie temperature, it was only 4 kJm -3 .

[0038] Fig. 3 shows Mn deposited at 300 °C 1.08 Fe 0.58 Pt 1.19The magnetization of a 44 nm Ga thin film is shown. The magnetization as a function of temperature (Figure 3a), measured in the magnetic field cooling mode (FC) with a magnetic field strength of 0.1 T, shows a phase transition from ferromagnetism to paramagnetism at approximately 312 K. The hysteresis curves measured at 50 K and 300 K in the out-of-plane geometric configuration are shown in Figure 3b, respectively. The coercive field strength was 0.87 T in the low-temperature measurement, while T C The reading measured nearby was 0.02T.

[0039] Both examples demonstrate that materials with a hexagonal crystal structure can exhibit considerable saturation coercivity and remanence in the presence of elements with sufficient unpaired electrons, such as manganese or iron, and elements with explicit spin-orbit coupling, such as platinum. Hexagonal Mn 1.08 Fe 0.58 Pt 1.19 The Ga system has also been shown to further increase both the Curie temperature and magnetic moment in a four-component system. Similar results can be achieved with the MnCoPtGa system.

Claims

1. A hard magnet, with a general composition X a X' b Y c Z d [In the formula, X and X' independently represent 3d transition metals with unpaired electrons; Y is a 4d or 5d transition metal of group 5, 8, 9, or 10; Z is a typical element of group 13, 14, or 15; a and d are independent of each other and represent numbers between 0.1 and 2.0; b represents a number between 0.0 and 2.0; c is 1; [Let a + b + c + d be between 3.0 and 4.0] It contains an intermetallic compound having Intermetallic compounds have hexagonal or trigonal symmetry. Having a saturation coercivity Bc of 0.05T or more, X is Mn, X' is Fe, Y is Pt, Z is Ga. The aforementioned hard magnet.

2. The hard magnet according to claim 1, wherein a is 1 or 2.

3. The hard magnet according to claim 2, wherein a is 1 when b is 1, and a is 2 when b is 0.

4. A hard magnet according to any one of claims 1 to 3, wherein d is 1.

5. A hard magnet according to any one of claims 1 to 4, wherein b is 0, or if a is 1, then b is 1.

6. The hard magnet according to any one of claims 1 to 5, wherein the sum of a, b, c, and d is 3.0 or 4.

0.

7. A hard magnet according to any one of claims 1 to 6, wherein the intermetallic compound has crystalline magnetic anisotropy.

8. A hard magnet according to any one of claims 1 to 7, which is sintered.

9. A hard magnet according to any one of claims 1 to 7, further comprising a binder.

10. A hard magnet according to any one of claims 1 to 9, wherein b is not 0.

11. A method for manufacturing a hard magnet, comprising either sintering an intermetallic compound or incorporating it into a binder, Intermetallic compounds generally have a composition of X a X' b Y c Z d [In the formula, X and X' represent 3d transition metals with unpaired electrons; Y is a 4d or 5d transition metal of group 5, 8, 9, or 10; Z is a typical element of group 13, 14, or 15; a and d represent numbers between 0.1 and 2.0, independently of each other; b represents a number between 0.0 and 2.0; c is 1, [Let a + b + c + d be between 3.0 and 4.0] It has, Furthermore, the method includes depositing an intermetallic compound on a sapphire or MgO substrate at a deposition temperature that results in hexagonal or trigonal symmetry. The hard magnet has a saturation coercivity Bc of 0.05 T or more. X is Mn, X' is Fe, Y is Pt, Z is Ga. The aforementioned method.

12. A hard magnet having a general composition X a X' b Y c Z d [In the formula, X and X' independently represent 3d transition metals with unpaired electrons; Y is Ru, Rh, Pd, Pt, Ir, Ag, or Au; Z is a typical element of group 13, 14, or 15; a and d are independent of each other and represent numbers between 0.1 and 2.0; b represents a number between 0.0 and 2.0 that is not 0.0; c is 1; [Let a + b + c + d be between 3.0 and 4.0] It contains an intermetallic compound having Intermetallic compounds have hexagonal or trigonal symmetry. The hard magnet has a saturation coercivity Bc of 0.05 T or more. X is Mn, X' is Fe, Y is Pt, Z is Ga. The aforementioned hard magnet.

13. A material having permanent magnetic properties, i) a hard magnet and ii) an epitaxial substrate selected from sapphire or MgO, wherein the hard magnet is placed on the epitaxial substrate. The hard magnet has a general composition X a X' b Y c Z d [In the formula, X and X' independently represent 3d transition metals with unpaired electrons; Y is a 4d or 5d transition metal of group 5, 8, 9, or 10; Z is a typical element of group 13, 14, or 15; a and d are independent of each other and represent numbers between 0.1 and 2.0; b represents a number between 0.0 and 2.0; c is 1; [Let a + b + c + d be between 3.0 and 4.0] It contains an intermetallic compound having The intermetallic compound has hexagonal or trigonal crystal symmetry, The hard magnet has a saturation coercivity Bc of 0.05 T or more. X is Mn, X' is Fe, Y is Pt, Z is Ga. The aforementioned material.

14. Hard magnets are made of Mn 1.5 PtGa or Mn 1.08 Fe 0.58 Pt 1.19 The material according to claim 13, wherein the material is Ga and the base material is sapphire.

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