Ferromagnetic material, method for manufacturing the same, and thin film

Abstract

To provide a new compound in an AlN-based ferromagnetic material having a wurtzite structure.SOLUTION: A ferromagnetic material is composed of the following A and B. A is composed of (Al(1-x), Mx). M is composed of one or more elements other than Al belonging to Group 3, Group 13, Group 14, or Group 15. x is greater than 0 and less than 1. B is composed of (N(1-y), Ry). R is composed of one or more elements belonging to Group 16 or Group 17. Y is greater than 0.05 and less than 1.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to ferromagnetic materials, thin films and methods for making ferromagnetic materials. [Background technology]

[0002] Non-Patent Document 1 discloses that an as-grown crystalline aluminum nitride (AlN) thin film induces dilute ferromagnetism at 300 K after isothermal annealing in a controlled oxygen environment. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] D. Nath, et al., J. Alloys and Compounds, Vol 967, 171727 (2023) Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is still room for improvement in the technology to provide new compounds in AlN-based ferromagnetic materials with wurtzite structure. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided a ferromagnetic material having a wurtzite crystal structure. The ferromagnetic material is composed of A and B. A is (Al (1-x) ,M x ). M is composed of one or more elements belonging to Group 3, Group 13, Group 14, or Group 15, other than Al. x is greater than 0 and less than 1. B is composed of (N (1-y) ,R y ) R is composed of one or more elements belonging to Group 16 or Group 17. y is greater than 0.05 and less than 1.

[0006] According to this configuration, a novel compound can be provided in the AlN-based ferromagnetic material having a wurtzite structure. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 illustrates an example of a magnetic device. [Figure 2] FIG. 2 is a diagram showing an example of the crystal structure of the ferromagnetic material according to the present embodiment before crystal field splitting due to lattice defects. [Figure 3] FIG. 3 is a diagram showing the crystal structure resulting from optimizing the crystal structure of the ferromagnetic material shown in FIG. 2 based on the crystal field splitting due to lattice defects VA. [Figure 4] An example of an energy level diagram for the crystal structure shown in Figure 3. [Figure 5] FIG. 10 is a diagram showing details of a localized level Ei. [Figure 6] Calculation Examples 1 to 9 are diagrams showing systems 1 to 9 in which one N is replaced with O. [Figure 7] FIG. 1 shows systems 10 to 12 in which two N's are replaced with O's. [Figure 8] FIG. 1 shows systems 13 to 16 in which three N's are replaced with O's. [Figure 9] This is a diagram showing systems 17 and 18 when four Ns are replaced with Os. [Figure 10] FIG. 10 is a diagram showing a calculation system 19, which is a system to be calculated according to calculation example 25. [Figure 11] 1 shows calculation systems 20 and 21, which are systems in which the number of lattice defects is two, among the systems to be calculated in this calculation. [Figure 12] FIG. 1 shows an MH curve (A) of Example 1 and an MH curve (B) of Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. Various features shown in the following embodiments can be combined with each other.

[0009] 1. Magnetic devices, etc. In this section, a magnetic device and a ferromagnetic material included in the magnetic device will be described. Fig. 1 is a diagram showing an example of a magnetic device. As shown in Fig. 1, the magnetic device 1 includes a substrate 11 and a thin film 12.

[0010] The substrate 11 may be made of any material, such as glass, film, or metal. Specifically, the substrate 11 may be made of silicon (especially p-doped silicon) to improve the stackability of the ferromagnetic material described below. The substrate 11 may also be made of a polyimide film or the like to provide flexibility to the substrate.

[0011] The thin film 12 is laminated on the substrate 11. The specific configuration of the shape of the thin film 12 is arbitrary, but for example, the film thickness of the thin film 12 laminated on the substrate 11 is preferably less than 1 μm. This allows the entire magnetic device to be made compact.

[0012] The thin film 12 includes a ferromagnetic material. FIG. 2 is a diagram showing an example of the crystal structure of the ferromagnetic material in this embodiment before crystal field splitting due to lattice defects. The ferromagnetic material has a wurtzite-type crystal structure and is composed of A and B. For example, if the lattice defect of A, which will be described later, is not taken into consideration, the ferromagnetic material is expressed by the general formula AB. Strictly speaking, if the lattice defect of A is taken into consideration, the ferromagnetic material is expressed by the general formula A (1-r)It can be represented as B. r represents the ratio of the number of sites where A is not arranged to the total number of sites where A can be arranged in the unit cell, that is, the so-called defect rate, and 0 < r < 1. The wurtzite-type structure is a hexagonal system with the space group of P63mc. The B sites where B is arranged are the fractional coordinates (1 / 3, 2 / 3, 0.374) and positions crystallographically equivalent to this. In general, in a hexagonal system such as the wurtzite-type structure, the lattice constant in the c-axis direction parallel to the six-fold rotation axis is larger than the lattice constants in the a-axis direction and the b-axis direction perpendicular to the six-fold rotation axis respectively.

[0013] A is a cation in the wurtzite structure, (Al (1-x) ,M x). M may be any atomic species that stabilizes the wurtzite structure. M may be, for example, one or more elements other than Al that belong to Group 3, Group 13, Group 14, or Group 15. Examples of elements belonging to Group 3 include Sc, Y, lanthanides, and actinides. Furthermore, as elements belonging to Group 3, elements that become nonmagnetic ions in a trivalent state, such as Sc, Y, and Lu, are particularly preferred. This can suppress the interference of the magnetic moment of M with the interaction between magnetic moments occurring at the A site. Furthermore, Sc is particularly preferred from the viewpoint of stabilizing the wurtzite structure. Examples of elements belonging to Group 13 include B, Ga, and In. These elements are preferred because they have properties similar to Al and are easier to substitute than other elements. The use of B, a relatively light element, can provide a magnetic device with a lower environmental impact. Examples of elements belonging to Group 14 include C, Si, Ge, and Sn. Among the elements belonging to Group 14, Si is particularly preferred from the viewpoint of compatibility with the substrate. Examples of elements belonging to Group 15 include N, P, and As. From the viewpoint of crystal stability, it is particularly preferable to use P. In other words, for example, M can be composed of one or more elements selected from the group 3 elements of B and Sc, the group 13 elements of Ga and In, the group 14 elements of Si, and the group 15 elements of P. This configuration has an outermost electron configuration relatively close to that of Al, making it easy to substitute for Al. More specifically, M can be composed of one or more elements selected from the group 3 elements of B and Sc, and the group 13 elements of Ga and In. This configuration has an electronic structure similar to that of Al, which has three unpaired electrons in an isolated state, making it even easier to substitute for Al. More specifically, M can be composed of Sc.

[0014] For example, x is greater than 0 and less than 1. That is, the ferromagnetic material is configured so that A does not consist solely of Al. More preferably, x is greater than or equal to 0.2 and less than or equal to 0.4 so that Al is the major component compared to M. Specifically, x may be 0.1, 0.2, 0.3, or 0.4, or may be within a range between any two of the values ​​exemplified here.

[0015] A can be located at the A site. The A site can be expressed in correspondence with the position where one of A is located and its crystallographically equivalent position. In this embodiment, the position where one of A is located is expressed by fractional coordinates (1 / 3, 2 / 3, 0). The ferromagnetic material in this embodiment has a lattice defect V in at least one of the A sites. A The device is configured to have:

[0016] B is the anion in the wurtzite structure, (N (1-y) ,R y ) R is composed of one or more elements belonging to group 16 or 17. As a result, R functions as an electron dopant at the B site. With this configuration, by substituting R for at least a part of N at the B site, lattice defects V at the A site can be eliminated. A The elements belonging to Group 16 can be O, S, Se, etc., and the elements belonging to Group 17 can be F, Cl, Br, I, etc. Preferably, R can be composed of at least one element selected from O, S, and Se, which are elements belonging to Group 16. With this configuration, R has an electronic structure that is relatively closer to that of N than that of Group 17 elements, and functions as an electron dopant, thereby improving the band occupancy rate of electron orbitals that exhibit magnetism, and providing a ferromagnetic material with stronger and superior magnetic properties. More preferably, R can be composed of O. With this configuration, the Curie temperature of the ferromagnetic material can be particularly increased, providing a ferromagnetic material with stronger magnetism.

[0017] y is a value representing the proportion of N substituted at the B site. y can be any value that allows the formation of a wurtzite structure. For example, y is greater than 0.05 and less than 1. Specifically, y can be 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9, or can be within a range between any two of the values ​​exemplified here. Preferably, y is greater than 0.05 and less than 0.4, more preferably 0.1 or greater and less than 0.3, and even more preferably 0.15 or greater and 0.2 or less. Generally, as y increases, the wurtzite structure becomes relatively unstable, and a phase with a crystal structure different from the wurtzite structure, such as AlScO (orthorhombic crystal system of space group Pnma), may appear. From this perspective, y is particularly preferably less than 0.3. In other words, ferromagnetic materials in which a part of N at the B site is inevitably replaced with M, which may be contained as an impurity, can be excluded.

[0018] B can be located at the B site. The B site can be expressed in correspondence with the position where one of B is located and its crystallographically equivalent position. In this embodiment, the position where one of B is located is represented by fractional coordinates (1 / 3, 2 / 3, 0.374).

[0019] As shown in FIG. 2, in this embodiment, one isolated lattice defect V A is adjacent to four Bs. As a result, the lattice defect V A The position of B adjacent to V changes from the state shown in FIG. 2. A The B adjacent to is denoted as Bd to distinguish it from other Bs. Figure 3 shows the crystal structure of the ferromagnetic material shown in Figure 2, with a lattice defect V A FIG. 4 shows an example of an energy level diagram for the crystal structure shown in FIG. 3. In FIG. 3, Bd is a lattice defect V A The interaction between V and Bd via the crystal field causes the lattice defect V AIt is displaced from the original position of B (i.e., the symmetric position) where it does not exist. As a result, as shown in FIG. 4, an interstitial level Ei formed by electrons localized around a lattice defect V is formed in the middle of the band gap between the valence band Ev and the conduction band Ec of the ferromagnetic material. A An interstitial level Ei formed by electrons localized around a lattice defect V is formed.

[0020] FIG. 5 is a diagram showing details of the interstitial level Ei. Note that the energy levels only show relative magnitudes, and it should be noted that the distances between the levels do not quantitatively represent the magnitude relationship of the energies.

[0021] The interstitial level Ei splits into one first level E1, two degenerate second levels E2, and one third level E3 due to crystal field splitting caused by the lattice defect V. The energies of the respective levels are E1 < E2 < E3. Among the outermost shell electrons of Bd, the electrons that should have been used for bonding with A due to the presence of the lattice defect V become surplus. Also, due to crystal field splitting around the lattice defect V, three of the four Bd among the surplus four electrons are present within the same (0001) plane (i.e., the ab plane), so they are in positions symmetric to the A site corresponding to the lattice defect V. Hereinafter, for convenience of explanation, each of the three B sites located within the same (0001) plane among the positions adjacent to the lattice defect may be referred to as the nearest-neighbor B site. On the other hand, one of the four B sites is separated in the c-axis direction. Therefore, the B site separated in the c-axis direction has a longer distance from the lattice defect V compared to the other three sites included in the same (0001) plane. Hereinafter, for convenience of explanation, among the B adjacent to the lattice defect V, the B separated from the lattice defect V in the c-axis direction may be referred to as the next-nearest-neighbor B. Also, B that is not adjacent to the lattice defect V, i.e., B other than the nearest-neighbor B and the next-nearest-neighbor B, may be referred to as the non-adjacent B. Therefore, the influence of the lattice defect on the electronic state of the nearest-neighbor B site tends to be greater than the influence on the electronic state of the next-nearest-neighbor B. ​​​​​​​​​​​​​​​​

[0022] Lattice defect V A There are four Bds adjacent to A, and 5 / 4 electrons from each Bd are left as dangling bonds with A. In the end, since there are four adjacent Bds, there is a lattice deficiency V A Five excess electrons are generated in the lattice, and the lattice vacancy V A Of these five excess electrons, three electrons are arranged with a magnetic moment, which results in a level in the band gap, i.e., a lattice defect V A By generating one, approximately 3μ B This will generate a magnetic moment of μ B represents the Bohr magneton. Thus, the lattice defect V A The existence of V is the origin of the magnetic moment in ferromagnetic materials, so it is necessary to create a lattice defect V while leaving electrons with magnetic moments. A It is preferable to increase the concentration of . On the other hand, the lattice defect V A Whether the entire material containing lattice defects V has ferromagnetic properties depends on the A It is determined by the strength of the exchange interaction between them and the temperature.

[0023] 2. Manufacturing methods for ferromagnetic materials Next, a method for manufacturing the ferromagnetic material described in the previous section will be described. The manufacturing method according to this embodiment uses a so-called sputtering method. Note that the ferromagnetic material can be formed into a film using any method, such as molecular beam epitaxy (MBE), and particularly, a semiconductor manufacturing method, without being limited to the sputtering method.

[0024] First, in the substrate preparation step, the substrate 11 is prepared on a sample stage in a vacuum chamber. As the substrate 11, for example, a Si substrate or a p-doped Si substrate can be used.

[0025] Next, in the substrate cleaning step, the surface of the prepared substrate 11 is cleaned. This allows the thin film containing the ferromagnetic material to be deposited more favorably. The specific cleaning method can be any method, but chemical cleaning can be used, for example. Chemical cleaning can be performed by cleaning the surface of the substrate 11 with a mixture of sulfuric acid and hydrogen peroxide, then cleaning the surface of the substrate 11 with hydrofluoric acid, and finally cleaning the reagents on the surface of the substrate 11 with ultrapure water. Note that by preparing a substrate that has undergone such surface treatment in the substrate preparation step, the cleaning step can be omitted.

[0026] Next, in the insulating film forming process, an insulating film is formed on the surface of the cleaned substrate 11. For example, in the insulating film forming process, an oxide film made of SiO2 is formed by heating a Si substrate used as the substrate 11. The thickness of the oxide film is arbitrary, specifically, for example, 100, 200, 300, 400, 500, 600, 700, 800, or 900 nm, and may be within a range between any two of the values ​​exemplified here. A thickness of 300 to 500 nm is particularly preferable for the oxide film. This prevents electrical leakage between the thin film 12 stacked on the oxide film and the substrate 11, which would otherwise cause a decrease in magnetic properties. Furthermore, the time required for the insulating film forming process can be shortened compared to when the oxide film is excessively thick. Note that this process can be omitted by preparing a substrate 11 on which an insulating film has been formed in advance.

[0027] Next, in the target placement step, a target is placed on a target stage at a predetermined position relative to the substrate 11 on which the insulating film is formed in the vacuum chamber. The target is an example of a base material configured to emit elements that constitute A, and is configured to be able to emit elements that constitute A of a ferromagnetic material. For example, the target is a bulk material made of elements that constitute A, for example, an alloy made of Al and Sc. The composition ratio of Al and Sc is arbitrary, but for example, the composition ratio of the target can be set to Al a Sc 1-awhere a is, for example, 0.3 to 0.7, preferably 0.4 to 0.6, and more preferably 0.5 to 0.6. In particular, a is preferably greater than 0.5 to increase the amount of Al relative to Sc in the ferromagnetic material. The target stage is configured to be able to perform sputtering of the target by creating a potential difference between the target stage and the substrate 11. The distance between the substrate 11 and the target is optional, and specific examples include 10, 20, 40, 60, 80, 100, 120, 140, 160, 180, and 200 mm, and may be within a range between any two of the values ​​exemplified here. The distance between the substrate 11 and the target is preferably 60 to 140 mm, more preferably 80 to 120 mm, to accelerate plasma particles emitted from the target.

[0028] Next, in the target cleaning process, the placed target is cleaned to remove metal contamination from the target and stage. Note that any cleaning method can be used, but for example, Ar plasma irradiation can be used to remove surface contamination.

[0029] Next, in the atmosphere adjustment step, the atmosphere in the vacuum chamber in which the substrate 11 and the target are placed is replaced with a predetermined gas, thereby exposing the substrate 11 to the gas. In this embodiment, the gas includes N2 gas and a reactive gas.

[0030] The N2 gas is used to introduce N ions, which are placed at the B site, into the particle beam emitted from the target.

[0031] The reactive gas is a gas containing elements that constitute M. For example, when M=O, the reactive gas is a gas containing O as an element, specifically O2 gas. The ratio of N2 gas to reactive gas can be appropriately set according to the amount of M to be introduced. For example, the (flow rate of reactive gas) / (flow rate of N2 gas) is, in units of sccm (standard cubic centimeters per minute), specifically, for example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, and may be within a range between any two of the values ​​exemplified here. In particular, it is preferable to have an appropriate concentration of lattice defects V while stabilizing the wurtzite structure. A In order to introduce N2 gas, it is preferable that the ratio of (flow rate of reaction gas) / (flow rate of N2 gas) is 0.01 or more and 0.05 or less. Note that the gas containing O as an element is not limited to O2 gas and can be any gas, such as O3.

[0032] The gas in this embodiment may contain an inert gas. This configuration facilitates adjustment of the concentration of elements such as N contained in the gas, thereby reducing variations in the composition ratio of the ferromagnetic material. The inert gas may be, for example, Ar gas, which has a lower reactivity with elements released from the target than N. When Ar gas is used as the inert gas, the ratio (flow rate of Ar gas) / (flow rate of N gas) may be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1 in SCCM, or may be within a range between any two of the values ​​exemplified here.

[0033] The atmosphere may be replaced in any manner. For example, the atmosphere in the vacuum chamber is first removed using a vacuum pump. The pressure in the vacuum chamber at this time may be any pressure, for example, 10 2 ,10,1,10 -1 ,10 -2 ,10 -3 ,10 -4 ,10 -5 ,10 -6 ,10 -7 ,10 -8The pressure is 10 Pa, and may be in the range between any two of the values ​​exemplified here. ―8 From the viewpoint of removing impurities contained in the atmosphere, the pressure inside the vacuum chamber after substitution can be set to 10 -7 Pa to 10 -5 It is preferable that the pressure in the vacuum chamber is so-called high vacuum, about 10 Pa. Next, the above gas is introduced into the vacuum chamber from which the atmosphere has been removed. The amount of gas introduced is arbitrary, but it is preferable that the gas is introduced so that the pressure in the vacuum chamber becomes low to medium vacuum, for example. Specifically, it is preferable that the pressure in the vacuum chamber becomes 10, 1, 10 -1 ,10 -2 ,10 -3 The gas is preferably introduced so that the pressure inside the vacuum chamber after the gas is introduced is preferably 0.1 to 10 Pa, more preferably 0.5 to 0.9 Pa, and even more preferably 0.7 to 0.85 Pa.

[0034] Next, in the film formation temperature setting step, the substrate 11 is heated to raise its temperature to a preset film formation temperature. The film formation temperature can be any temperature as long as it activates the N element contained in the material constituting the target so that it is replaced with M contained in the reactive gas. Specifically, the film formation temperature can be, for example, 200, 250, 300, 350, 400, 450, or 500°C, or can be within a range between any two of the values ​​exemplified here. In particular, to improve the reactivity between the gas derived from the target and M contained in the reactive gas while suppressing deterioration of the substrate 11, the film formation temperature is preferably 300°C or higher and 500°C or lower, more preferably 350°C or higher and 450°C or lower, and even more preferably 370°C or higher and 430°C or lower. The atmosphere adjustment step and the film formation temperature setting step may be performed in parallel or in reverse order.

[0035] Next, in the lamination step, A is released from the target in the atmosphere adjusted in the atmosphere adjustment step, thereby laminating a ferromagnetic material on a substrate, thereby producing a thin film 12. For example, in the lamination step, A is released from the target by a sputtering method in the above atmosphere, and a ferromagnetic material is laminated on a substrate 11, thereby producing a thin film 12 and a magnetic device 1 including the thin film 12. While any specific mode of sputtering is possible, for example, the sputtering power may be, for example, 100, 150, 200, 250, 300, 350, or 400 W, or may be within a range between any two of the values ​​exemplified here. Furthermore, the bias voltage may be, for example, 50, 100, 150, 200, 250, or 300 V, or may be within a range between any two of the values ​​exemplified here. From the viewpoint of stability, a voltage of 200 to 300 V is particularly preferable. The current flowing through the target at this time is arbitrary, but specific examples include 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, and 2.5 A, and may be within a range between any two of the values ​​exemplified here.

[0036] In other words, the magnetic device 1, thin film 12, and ferromagnetic material can be obtained through these steps.

[0037] 3.Other The above-described embodiment can be modified as appropriate based on the following aspects.

[0038] The thin film can be deposited by any method, such as chemical vapor deposition (CVD) such as chemical vapor transport, without being limited to sputtering or MBE.

[0039] The ferromagnetic material is not limited to a thin film, but may also be a bulk material. A bulk ferromagnetic material can be obtained by any of various available crystal growth methods, such as chemical vapor transport, floating zone (FZ), and flux growth, using the above-described thin film as a seed crystal. In this case, a bulk material having a composition and structure similar to that of this embodiment may be obtained by reacting a previously obtained parent material with a wurtzite structure (e.g., AlN or (Al,Sc)N) in an oxygen atmosphere. Alternatively, a bulk ferromagnetic material can be synthesized by stacking the ferromagnetic material on a substrate, adjusting the stacking time to form a bulk material.

[0040] The above manufacturing method is also applicable to ferromagnetic materials in which y is less than 0.05. Note that y=0.05 is merely an example of the amount of R contained as an unavoidable impurity in an (Al,Sc)N system.

[0041] The target used in the above manufacturing method may be Al metal without containing Sc. In other words, the ferromagnetic material manufactured by the above manufacturing method is not limited to one containing Sc as A, and may be Al(N,R).

[0042] The above embodiment may be provided in the following aspects.

[0043] (1) A ferromagnetic material having a wurtzite crystal structure, which is composed of A and B, and A is (Al (1-x) ,M x ), wherein M is composed of one or more elements other than Al belonging to Group 3, Group 13, Group 14, or Group 15, wherein x is greater than 0 and less than 1, and B is composed of (N (1-y) ,R y ) wherein R is one or more elements belonging to group 16 or 17, and y is greater than 0.05 and less than 1.

[0044] (2) The ferromagnetic material according to (1) above, wherein R is composed of at least one element selected from O, S, and Se, which are elements belonging to Group 16.

[0045] (3) The ferromagnetic material according to (2) above, wherein the R is O.

[0046] (4) The ferromagnetic material according to (3) above, wherein y is greater than 0.05 and equal to or less than 0.4.

[0047] (5) The ferromagnetic material according to any one of (1) to (4) above, wherein M is composed of one or more elements selected from the group consisting of B and Sc as elements belonging to group 3, Ga and In as elements belonging to group 13, Si as an element belonging to group 14, and P as an element belonging to group 15.

[0048] (6) The ferromagnetic material according to (5) above, wherein M is composed of one or more elements selected from the group consisting of B and Sc as elements belonging to group 3, and Ga and In as elements belonging to group 13.

[0049] (7) The ferromagnetic material according to (6) above, wherein M is composed of Sc.

[0050] (8) The ferromagnetic material according to (7) above, wherein x is 0.2 or more and 0.4 or less.

[0051] (9) The ferromagnetic material according to any one of (1) to (8) above, wherein the R is arranged in at least one of the B sites where the B is arranged, adjacent to a lattice defect in the A site where the A is arranged.

[0052] (10) A thin film laminated on a substrate, the thin film comprising the ferromagnetic material according to any one of (1) to (9) above.

[0053] (11) The thin film according to (10) above, wherein the thickness of the thin film is less than 1 μm.

[0054] (12) A method for producing a ferromagnetic material, the ferromagnetic material being composed of A and B, wherein A is (Al (1-x) ,M x ), wherein M is composed of one or more elements other than Al belonging to Group 3, Group 13, Group 14, or Group 15, wherein x is 0 or more and less than 1, and wherein B is composed of (N (1-y) ,R y ), wherein R is composed of one or more elements belonging to Group 16 or Group 17, and y is greater than 0 and less than 1. The manufacturing method includes the following steps: a substrate preparation step of preparing a substrate; an atmosphere adjustment step of exposing the substrate to an atmosphere composed of a gas containing N and R as elements; and a lamination step of releasing elements constituting A toward the substrate in the atmosphere, thereby manufacturing the ferromagnetic material laminated on the substrate.

[0055] (13) The method according to (12), wherein R is O.

[0056] (14) The manufacturing method according to (13) above, wherein the gas includes O2 gas.

[0057] (15) In the manufacturing method according to any one of (12) to (14) above, in the laminating step, the ferromagnetic material is laminated on the substrate by releasing the elements constituting A from a predetermined base material by a sputtering method or a molecular beam epitaxy method in the atmosphere.

[0058] (16) The manufacturing method according to any one of (12) to (15) above, wherein the ferromagnetic material is the ferromagnetic material according to any one of (1) to (11) above. Of course, this is not the case.

[0059] Finally, while various embodiments of the present disclosure have been described, they are presented as examples and are not intended to limit the scope of the invention. The novel embodiments may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. Such embodiments and modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the inventions and their equivalents as defined in the claims.

[0060] 4. Theoretical calculations The inventors performed theoretical calculations on the above ferromagnetic material and elucidated the mechanism of its ferromagnetic manifestation. Specifically, the inventors found that the magnetism of the above ferromagnetic material is due to the lattice deficiency V A The magnetic moment of the surrounding ligands is the origin of the lattice defect V A We found that the presence of M, such as O, stabilizes the ferromagnetism. In this section, we explain the theoretical calculation method, results, and discussion on the mechanism of ferromagnetism.

[0061] 4.2. Lattice Defect V A On the calculation of the total energy of the system Al(N,O) containing The inventors have investigated the lattice defects V when M is introduced into the crystal structure shown in FIG. A The energy generated by the formation of V (hereinafter referred to as the formation energy) is calculated. A We have found new knowledge about the stability of lattice defects V for each M introduction mode. A The calculation results of the formation energy of

[0062] 4.2.1. Calculation method In this section, we explain the calculation method for formation energy, etc.

[0063] First, we will explain the specific system for calculating the formation energy. A The AlN system (hereinafter referred to as the basic system) having the lattice defect V is defined as shown in the table below.A If the number of A's is n, then it consists of (54-n) A's and 54 B's. [Table 1]

[0064] The inventors have obtained a system (hereinafter, for convenience of explanation, referred to as a calculation system) that is obtained by substituting some of the N contained in such a basic unit cell with O.

[0065] Next, the inventors calculated the energy eigenvalues ​​of the Hamiltonian corresponding to each of the set systems by first-principles calculations based on density functional theory (DFT). VASP was used as the code for calculating DFT. Furthermore, the functional used in the density functional calculations was generally PBE (Perdew-Burke-Ernzerhof) as a generalized gradient approximation (GGA). A cutoff energy of 500 eV was adopted. The cutoff energy is a quantity that indicates the maximum kinetic energy of a plane wave that can be used as an expansion basis when expressing electron density in a plane wave basis. The Hamiltonian used in the calculations was defined as follows:

number

[0066] Here, the first term on the right-hand side represents the single-particle kinetic energy, the second term represents the potential from the atomic nucleus, the third term represents the Hartree potential, and the fourth term represents the exchange-correlation potential.

[0067] Based on such DFT, the inventors have determined the lattice defect V in the system set as the calculation target. A The inventors calculated the band structure and density of states in the crystal field near the lattice. From the obtained band structure and density of states, they determined the lowest energy eigenvalue of the system (in other words, the most stable state) and the state of one lattice defect V. A The magnetic moment per

[0068] 4.2.2. Regarding the system for calculating the formation energy when some of the N in the system is replaced with M=O in the case of A=Al In this section, calculation examples 1 to 18 of the energy of the entire system will be described when A=Al and M=O and some of the N contained in the system are substituted with M=O. Calculation examples 1 to 9 are for the case where the number of N substitutions is one. FIG. 6 is a diagram showing systems 1 to 9 in calculation examples 1 to 9 when one N is substituted with O. FIG. 7 is a diagram showing systems 10 to 12 when two N are substituted with O. FIG. 8 is a diagram showing systems 13 to 16 when three N are substituted with O. FIG. 9 is a diagram showing systems 17 and 18 when four N are substituted with O. Details of calculation systems 1 to 18 for calculation examples 1 to 18 are as shown in the table below. [Table 2]

[0069] The definitions of nearest neighbor N, next nearest neighbor N, and non-adjacent N are the same as those of nearest neighbor B etc. described above.

[0070] 4.2.3. Calculation results Next, the energy of the calculation system in each of the above calculation examples 1 to 18 and one lattice defect V A The calculation results for each of Calculation Examples 1 to 18 and their considerations are as follows: [Table 3]

[0071] The relatively low energy of the system indicates that the ferromagnetic material preferentially adopts the structure shown in the system according to the calculation example. Comparing calculation examples 1 to 9, the energy of the system is as follows: when the nearest neighbor N is substituted with O (calculation example 1: approximately -792.7 eV), when the next nearest neighbor N is substituted with O (calculation example 2: approximately -792.5 eV), and when the non-neighbor N is substituted with O (calculation examples 3 to 9: approximately -791 eV). This is because O is a lattice vacancy V. A The closer to V, the greater the lattice defect AThis means that the presence of is stabilized. Also, (energy of the system in Calculation Example 2) - (energy of the system in Calculation Example 1) = 0.18 eV, while (energy of the system in Calculation Example 3) - (energy of the system in Calculation Example 1) = 1.29 eV, which is a difference of about 7 times in energy between the two systems. This suggests that when one N is substituted with O, the probability of substituting the nearest-neighbor N or the next-neighbor N (in other words, the adjacent N) is much higher than the probability of substituting the non-adjacent N.

[0072] Comparing the energies of the systems in calculation examples 10 to 12, even when the number of substitutions is 2, it is found that the substituted N is replaced by a lattice vacancy V, just as when the number of substitutions is 1. A It can be seen that the closer the number of substitutions is to , the lower the energy of the system. Similarly, the same is true for calculation examples 13 to 15 where the number of substitutions is 3, and calculation examples 17 and 18 where the number of substitutions is 4. In particular, when the number of substitutions is 1 to 3, the energy of the system is minimum when all substituted Ns are the nearest Ns.

[0073] Furthermore, comparing calculation examples 1, 11, 13, and 16, in which the energy of the system is minimized for each substitution number, we see that as the number of substitutions increases from 1 to 3, the energy of the system decreases, but when the number of substitutions increases from 3 to 4, the energy of the system actually increases.

[0074] On the other hand, by increasing the number of substitutions, one lattice defect V A The magnetic moment per lattice vacancy V decreases, and when the number of substitutions is 4, the magnetic moment becomes 0 and disappears. A It is suggested that it is preferable to determine the amount of reactive gas (O2) introduced when producing a ferromagnetic material so that the number of substitutions per atom is about 1 to 2.

[0075] 4.3. Lattice Defect V A On the formation energy of Next, the inventors investigated the most stable structure for each substitution number by examining the lattice vacancy V in the AlN system. AThe energy required to introduce O was calculated, and the lattice defect V A We have found that the formation energy of the ferromagnetic material decreases, and that the introduction of a reactive gas (O2) is useful for producing the ferromagnetic material. Below, we will explain the calculation method for the formation energy and the calculation results.

[0076] 4.3.1. Calculation method of formation energy First, we will explain how to calculate the formation energy. The formation energy is calculated using the following formula: formation is shown by

number

[0077] Equation (1) represents the formation energy in an environment rich in Al element, and Equation (2) represents the formation energy in an environment rich in N element. complex shows the total energy of each of the calculation systems 1 to 18, where there are (54-x) Al atoms, (54-y) N atoms, and y O atoms. E AlN is the total energy of the chemical composition unit of a perfect crystal of AlN without defects. μ Al is the chemical potential of Al in the case of bulk Al. μ N is the chemical potential of N for N molecules. μ O is the chemical potential of the oxygen molecule O. x is the number of Al atoms or Al vacancies V included in calculation systems 1-18. A y is a parameter indicating the number of O atoms contained in calculation systems 1 to 18. AlN =-14.8907eV,μ Al =-3.7469eV,μ N =-8.3133eV,μ O =-4.9249 eV.

[0078] 4.3.2. Calculation method of formation energy The inventors have calculated the formation energies (E formation ) was calculated using equations (1) and (2), respectively, to obtain calculation examples 19 to 23. First, the systems corresponding to calculation examples 19 to 23 will be explained.

[0079] Calculation example 19 is for one lattice defect V A where the number of substitutions of N is 0, that is, the calculation results of the formation energy in the basic system described above are shown.

[0080] Calculation example 20 is for one lattice defect V A The calculation results of the formation energy for calculation system 1, which is the most stable system among systems with a substitution number of N of 1, are shown below.

[0081] Calculation example 21 is for one lattice defect V A The calculation results of the formation energy of the most stable system among systems having the above structure and where the number of N substitutions is 2, that is, calculation system 11, are shown below.

[0082] Calculation example 22 is a calculation of one lattice defect V A The calculation results of the formation energy of the most stable system among systems having the above structure and where the number of N substitutions is 3, that is, calculation system 13, are shown below.

[0083] Calculation example 23 is a calculation of one lattice defect V A The calculation results of the formation energy of the most stable system among systems having the above structure and where the number of N substitutions is 4, that is, calculation system 16, are shown below.

[0084] The inventors calculated the formation energy for each of the above systems. The calculation results of the formation energy in Calculation Examples 19 to 23 are shown in the table below. [Table 4]

[0085] From the table above, it is clear that by changing the substitution number from 0 to 1, the formation energy of AlN decreases by about 15 to 21%, regardless of whether the environment is rich in Al or rich in N. This is because substituting N with O reduces the lattice vacancy V. A Furthermore, when the number of substitutions is two or more, the formation energy is negative in both equations (1) and (2). This indicates that the lattice vacancy V A It is actually more energetically advantageous to generate the lattice defect V, and the Al(N,O) related to the ferromagnetic material spontaneously generates the lattice defect V. A As mentioned above, the lattice defect V A is the origin of ferromagnetism in ferromagnetic materials with a wurtzite structure. For example, in the case of AlN, by introducing a gas containing O (especially O2 gas) as an element in the manufacturing atmosphere, N is replaced with O, and more lattice defects V are generated. A The theoretical calculations above revealed that this can stably form N, improving the magnetic properties of ferromagnetic materials, such as saturation magnetization. Furthermore, this reduction in formation energy is due to electron doping caused by substituting O for N. Therefore, it is suggested that the element capable of reducing the formation energy by substituting N is not limited to O, but can also be any element that acts as an electron dopant when substituted for N, such as S and Se, which belong to Group 16 like O, or F, Cl, Br, and I, which belong to Group 17.

[0086] In summary, it is preferable that at least one of M is arranged in a B site adjacent to an A site constituting a lattice defect, among B sites crystallographically equivalent to the site where B is arranged. With such a configuration, the lattice defect V A Further reducing the energy required to generate lattice defects, A It is more preferable that M is located at at least one of the nearest B sites. With this configuration, the lattice deficiency V Acan be stabilized.

[0087] 4.4. Lattice defects V when Al is replaced with other elements (M) A On the formation energy of The inventors also performed theoretical calculations on the change in formation energy when Al is substituted with Si, which is an example of M, and found that the formation energy decreases, similar to when N is substituted with an electron dopant such as O. Si is an example of an element that functions as an electron dopant for Al.

[0088] 4.4.1. Calculation method of formation energy The calculation method for the formation energy in this calculation will be explained. The formation energy is calculated using the following E formation is shown by

number

[0089] In addition, in formulas (4) to (6), the same symbols as in formulas (1) to (3) above indicate the same parameters and have the same values. Formula (4), like formula (1), indicates the formation energy in an environment where Al element is abundant, and formula (5), like formula (2), indicates the formation energy in an environment where N element is abundant. In formulas (4) and (5), E related to this calculation complex shows the total energy of the calculation system in which there are (54-x-y) Al atoms, 54 nitrogen atoms, and y Si atoms. x is the number of vacancies V of Al atoms introduced into the system by substitution. A y is a parameter corresponding to the amount of Si atoms introduced into the system by substitution. μ Si indicates the chemical potential for bulk Si, which is set to -5.4249 eV in this calculation. AlN ,μ Al ,μ N is the same as the value mentioned above.

[0090] 4.4.2. Calculation method of formation energy The inventors have calculated the formation energies (E formation ) was calculated using equations (4) and (5). First, the systems corresponding to calculation examples 24 and 25 will be explained.

[0091] Calculation example 24 is a calculation example with one lattice defect V A The calculation results of the formation energy for the basic system described above are shown below.

[0092] Calculation example 25 is a calculation example with one lattice defect V A Calculation results of the formation energy in a system having a lattice defect V A One of the nearest neighboring Al atoms is replaced by Si.

[0093] The inventors calculated the formation energy for each of the above systems. The calculation results for the formation energies in Calculation Examples 24 and 25 are shown in the table below. [Table 5]

[0094] From the above table, it is clear that by changing the substitution number of Al from 0 to 1, the formation energy of Al vacancies in AlN is dramatically reduced, regardless of whether the environment is rich in Al or rich in N. This is because by substituting one of the Al atoms with Si, the lattice vacancies V A This shows that the formation energy is lowered by electron doping due to the substitution of Al with Si. This indicates that electron doping at the Al site increases the number of lattice vacancies, V. AThe theoretical calculations above revealed that the formation energy can be stably formed by substituting Al, and that this can improve the magnetic properties of the ferromagnetic material, such as saturation magnetization. Note that the element capable of lowering the formation energy by substituting Al is not limited to Si, and it is suggested that any element that acts as an electron dopant by substituting Al, such as an element belonging to Group 14 like Si (C, etc.) or an element belonging to Group 15 (P, etc.), may also be used.

[0095] 4.5. Lattice Defect V A Theoretical calculations of magnetic properties of ferromagnetic materials with the introduction of α and N substitution Furthermore, the inventors performed theoretical calculations on physical quantities that indicate the magnetic properties of a system when N is replaced by various elements R, including O. Figure 11 shows calculation systems 20 and 21, which are systems that are the subject of this calculation and have two lattice defects. Calculation system 20 is a system with two lattice defects V. A It corresponds to AlN with two lattice defects V A are located at adjacent Al sites. Calculation system 21 shows a system in which two of the N atoms in calculation system 20 are replaced with elements other than N, R. Each of the two R atoms is a different lattice defect V. A are introduced into the nearest N positions of each of

[0096] The inventors performed various theoretical calculations on magnetism in each calculation system using the number of lattice defects, the number of N substitutions, and the number of elements introduced as R as parameters. A The calculation system for the case where (number of substitutions, number of substitutions) = (1, 0) is the same as the basic form shown in Figure 3. A The calculation system for the case where (number of substitutions, number of substitutions) = (1,1) is the same as calculation system 1. A The calculation system for the case where (number of substitutions, number of substitutions) = (2, 0) is the calculation system 20 described above. A The calculation system when (number of elements, number of permutations)=(2,2) is the calculation system 21 described above.

[0097] As a specific calculation method, the inventors constructed a Heisenberg Hamiltonian based on density functional theory, and calculated the Curie temperature T C MFA The Hamiltonian includes the spin exchange interaction J ij Parameters for the magnetic anisotropy energy and the magnetic field were introduced. In the density functional calculation, the parameters of the Heisenberg Hamiltonian were calculated using the OpenMX code. The functional used was the PBE (Perdew-Burke-Ernzerhof), which is commonly used as a generalized gradient approximation (GGA). The cutoff energy (a quantity that indicates the maximum plane wave kinetic energy that can be used as the expansion basis when expressing the electron density in a plane wave basis) was set to 1000 eV. In addition, the exchange interaction J ij The Liechtenstein formula was used to calculate

[0098] The table below shows the calculation conditions for each calculation example 26 to 39 (lattice defect V A the number of substitutions, the number of elements introduced as R) and the calculation results (magnetic moment, exchange integral J0, and Curie temperature T C MFA ) is shown. [Table 6]

[0099] The above calculation results show that even if N is replaced by an element other than O, the lattice vacancy V A In addition, when R=O is adopted, the Curie temperature T C MFA It can be seen that the value of O is significantly increased compared to when other elements are used for R, and is also increased by about 20% compared to when no N is substituted. This theoretically shows that substituting N with O is particularly preferable for improving the magnetic properties of ferromagnetic materials compared to substitution with other elements.

[0100] 5. About the Examples The inventors have experimentally demonstrated the accuracy of the theoretical calculations by preparing samples according to Examples 1 to 3 and evaluating their magnetic properties as further specific examples of the above-described embodiment. In this section, we will explain the manufacturing method and evaluation results of the samples for each Example. In each Example, the film formation conditions were adjusted so that M=Sc and R=O.

[0101] 5.1. Sample preparation Example 1 The procedure for preparing the sample according to Example 1 will be described.

[0102] [Preparing the board] First, the substrate preparation procedure will be described. In producing the sample according to Example 1, the inventors first prepared a p-type Si substrate (manufactured by Furuuchi Chemical Co., Ltd.) as a substrate. Next, the inventors chemically cleaned the prepared p-type Si substrate by cleaning the Si substrate with sulfuric acid and hydrogen peroxide, and then rinsed the Si substrate with hydrofluoric acid and ultrapure water. Thereafter, the substrate was subjected to a heat treatment to form a 400 nm thermally oxidized SiO2 film.

[0103] [Sample preparation] Next, the procedure for preparing a sample using the above substrate will be described. First, a target was placed in the chamber of a sputtering device (manufactured by Eiko Co., Ltd.). The target was a 80 mm diameter target with a composition ratio of Al. 0.57 Sc 0.43 The alloy was used. Next, the substrate was placed on the sample stage in the chamber. The distance between the target and the sample stage was 100 mm.

[0104] Next, the pressure in the chamber is increased to an ultra-high vacuum, specifically 10 -6The pressure inside the chamber was reduced until the pressure reached 0.79 Pa or less. Next, the inventors heated the substrate placed on the sample stage to 400°C, which is the film formation temperature. Next, 5 sccm of Ar gas (purity 99.9999%), 10 sccm of N2 gas (purity 99.9999%), and 0.2 sccm of O2 gas (purity 99.999%) were introduced into the chamber. As a result, the pressure inside the chamber rose to 0.79 Pa.

[0105] Thereafter, sputtering was performed in an atmosphere containing the introduced gas, and the sample was deposited on the substrate. The sputtering power was set to DC 300 W, the bias voltage to 250 V, and the substrate current to 1.12 A. The deposition time (sputtering time) was 9 minutes and 42 seconds. This resulted in a thin-film sample deposited on the substrate. The sample thickness was 100 nm. The sample thickness was measured at one point in the center of the sample.

[0106] <Example 2> Next, a sample preparation procedure according to Example 2 will be described. Note that explanations of points common to Example 1 may be omitted. In Example 2, a p-type Si substrate was chemically cleaned and then sputtered to obtain a thin-film sample on the substrate, as in Example 1. The sample had a thickness of 50 nm. Note that Example 2 differs significantly from Example 1 in that the amount of O2 gas contained in the introduced gas is greater than that in Example 1. Specifically, the introduced gas in Example 2 is composed of 5 sccm of Ar gas, 10 sccm of N2 gas, and 0.4 sccm of O2 gas. Example 2 also differs from Example 1 in that the substrate current is 1.20 A and the film formation time is 5 minutes and 19 seconds, which is shorter than that in Example 1.

[0107] Example 3 In Example 3, a p-type Si substrate with TiN laminated thereon was used as the substrate, and chemical cleaning was performed using the same procedure as for the p-type Si substrates in Examples 1 and 2. Example 3 differs significantly from Examples 1 and 2 in that no O2 gas was introduced (O2 gas flow rate: 0.0 sccm). Example 3 also differs from Examples 1 and 2 in that the substrate current was 1.20 A and the film formation time was 12 minutes and 30 seconds. Other differences are the same as in Example 1. As a result, a thin film sample laminated on a substrate was obtained in Example 3 as well. The sample had a thickness of 100 nm.

[0108] The manufacturing conditions for the samples according to Examples 1 to 3 can be compared as shown in the table below. [Table 7]

[0109] 5.2. Evaluation of samples 5.2.1. Evaluation method of the crystalline phase and composition of the sample First, the method for evaluating the crystalline phase and composition of the sample will be described.

[0110] The inventors performed X-ray diffraction measurements on the samples according to Examples 1 to 3 described above, and identified the crystalline phases from the peak positions and intensity ratios in the obtained X-ray patterns in the out-of-plane direction.

[0111] Furthermore, the inventors etched the surface of each sample according to Example 1 with Ar gas to reduce the thickness of the sample to approximately half, and then performed X-ray photoelectron spectroscopy (XPS) measurement to obtain a photoelectron spectrum. The composition ratio of the sample according to Example 1 was identified from the obtained photoelectron spectrum. Meanwhile, secondary ion mass spectroscopy (SIMS) measurement was performed on the same sample to obtain the ion intensity corresponding to the O contained in the sample. The obtained O ion intensity was then compared with the photoelectron spectrum, and the O ion intensity obtained by the SIMS measurement was correlated with the amount of O in the composition ratio identified by the XPS measurement. A calibration table was then obtained for the O ion intensity obtained by the SIMS measurement and the composition ratio in the (Al,Sc)(N,O) system. Note that, assuming that the amount of lattice defects contained in the sample was extremely small, the composition ratio of A = (Al,Sc) and B = (N,O) was calibrated to be 1:1.

[0112] In Examples 2 and 3, SIMS measurements were performed in the same manner as in Example 1, and the ion intensity corresponding to O contained in the sample was obtained. Here, in Examples 2 and 3, in consideration of the fact that a common target was used, (1) Each sample is composed of Al, Sc, N, and O. (2) The composition ratio of Al and Sc is the same as that of the sample according to Example 1. Based on this assumption, the composition ratios of the samples according to Examples 2 and 3 were estimated based on the calibration table for XPS in Example 1.

[0113] 5.2.2. Evaluation method for the magnetic properties of samples Next, the method for evaluating the magnetic properties of the samples will be described. First, the inventors cut the samples according to Examples 1 to 3 into 5 mm x 5 mm pieces. Next, the cut samples were fixed in non-magnetic straws. Next, the samples were set in an MPMS3 (manufactured by Quantum Design) so that a magnetic field was applied perpendicular to the surface of the substrate. After that, the sample temperature was set to 26°C, and the MH curves of the samples were measured using the VSM mode in a magnetic field of 3000 Oe.

[0114] 5.2.2. Evaluation results and discussion The evaluation of the above-described samples yielded the results shown in the table below for each of Examples 1 to 3. The lattice constants are those of the wurtzite structure phase. [Table 8]

[0115] From the above results, it was found that in Example 1, a ferromagnetic material was obtained in the case where M = Sc, R = O, x = 0.3, and y = 0.1, among the ferromagnetic materials according to the above embodiments. In Example 2, it was found that a ferromagnetic material was obtained in the case where M = Sc, R = O, x = 0.3, and y = 0.2. In Example 3, it was found that a ferromagnetic material was obtained in the case where M = Sc, R = O, x = 0.3, and y = 0.05. Note that in Example 3, O was detected even though the introduced gas did not contain O gas, suggesting that O at a composition ratio of approximately 0.05 is an impurity that is inevitably mixed in due to circumstances that are impossible or impractical to control, such as the degree of vacuum or O element adhering to the inner wall of the chamber.

[0116] In Example 1, a wurtzite structure phase, which is an example of a ferromagnetic material according to this embodiment, was obtained in a substantially single phase. On the other hand, in Example 2, it was found that in addition to the wurtzite structure phase, which is an example of a ferromagnetic material according to this embodiment, a phase corresponding to an orthorhombic AlScO3 was also present. This suggests that when the substitution rate of N with O is low, the wurtzite structure phase, which is an example of a ferromagnetic material according to this embodiment, is the most stable, whereas when the substitution rate of N with O increases and exceeds a certain level, the wurtzite structure phase, which is an example of a ferromagnetic material according to this embodiment, becomes relatively unstable compared to other phases.

[0117] Since Examples 1 and 2 have 2.7 times the saturation magnetization of Example 3, it was found that by preparing samples in an O-containing atmosphere, such as one containing O2 gas as an introduced gas, the magnetic properties can be significantly improved compared to preparing samples in an O-free atmosphere. Furthermore, as mentioned above, although it is estimated that the abundance ratio of the wurtzite structure phase is reduced in Example 2, the wurtzite structure phase has a higher saturation magnetization than Example 1, which was obtained as a single phase. This suggests that the wurtzite structure phase contained in the sample of Example 2 has a significantly higher saturation magnetization than the wurtzite structure phase contained in the sample of Example 1. Based on the results of the theoretical calculations above, this result suggests that the substitution of N in AlN with O and the lattice defect V A By lowering the formation energy of A The dramatic increase in the concentration of V A This suggests that the magnetic moment due to

[0118] FIG. 12 shows the MH curve (A) of Example 1 and the MH curve (B) of Example 3. As shown in FIG. 12, a ferromagnetic MH hysteresis loop was observed in Example 1. This indicates that the samples according to Example 1 and the like have ferromagnetic magnetic properties similar to those before and after the substitution. Furthermore, in the MH curve of Example 1, magnetic saturation was clearly observed at an external magnetic field of about 800 Oe, whereas in Example 3, the change in magnetization was gradual, and no bending point suggestive of magnetic saturation was observed until about 2000 Oe. This indicates that the energy required to cause magnetic saturation is reduced by substituting N with O, and therefore the soft magnetic material has a superior magnetic response speed compared to conventional AlN-based ferromagnetic materials.

[0119] From the above, by intentionally substituting N in AlN with an element that can be doped with electrons such as O, the lattice vacancy V A The results of the theoretical calculations above, that is, increasing the concentration of , improves the magnetic properties, were experimentally proven by Examples 1 to 3.

[0120] The inventors fabricated a sample using a gas mixture consisting of 5 sccm of Ar gas, 10 sccm of N gas, and 0.3 sccm of O gas for a deposition time of 4 minutes and 54 seconds using the same method as in Example 1. The results showed that the composition ratio of Al:Sc:O:N = 0.7:0.3:0.2:0.8, i.e., a ferromagnetic material with M = Sc, R = O, x = 0.3, and y = 0.2, was obtained. This indicates that the N substitution ratio y according to the embodiment can be adjusted by controlling the amount of O introduced. In this case, as in Example 1, a wurtzite structure, an example of a ferromagnetic material according to the present embodiment, was obtained in a nearly single phase. Since this sample has a composition intermediate between that of the sample according to Example 1 and that of Example 2, it is estimated that it has a saturation magnetization at least higher than that of the sample according to Example 1. [Explanation of symbols]

[0121] 1: Magnetic devices 11: Substrate 12: Thin film

Claims

1. A ferromagnetic material having a wurtzite crystal structure, It is composed of A and B, The A is (Al （１－ｘ） , M ｘ ) is composed of M is composed of one or more elements other than Al that belong to Group 3, Group 13, Group 14, or Group 15, x is greater than 0 and less than 1; The B is (N （１－ｙ） , R ｙ ) is composed of R is composed of one or more elements belonging to Group 16 or Group 17, A ferromagnetic material, wherein y is greater than 0.05 and less than 1.

2. 2. The ferromagnetic material according to claim 1, The R is a ferromagnetic material composed of at least one element selected from O, S, and Se, which are elements belonging to Group 16.

3. 3. The ferromagnetic material according to claim 2, The R is a ferromagnetic material composed of O.

4. 4. The ferromagnetic material according to claim 3, A ferromagnetic material, wherein y is greater than 0.05 and less than or equal to 0.

4.

5. 2. The ferromagnetic material according to claim 1, The M is a ferromagnetic material composed of one or more elements selected from the group consisting of B and Sc as elements belonging to Group 3, Ga and In as elements belonging to Group 13, Si as an element belonging to Group 14, and P as an element belonging to Group 15.

6. 6. The ferromagnetic material according to claim 5, The M is a ferromagnetic material composed of one or more elements selected from the group consisting of B and Sc as elements belonging to Group 3, and Ga and In as elements belonging to Group 13.

7. 7. The ferromagnetic material according to claim 6, The M is a ferromagnetic material composed of Sc.

8. 8. The ferromagnetic material according to claim 7, A ferromagnetic material, wherein x is equal to or greater than 0.2 and equal to or less than 0.

4.

9. 2. The ferromagnetic material according to claim 1, A ferromagnetic material configured such that R is disposed in at least one B site where B is disposed and adjacent to a lattice defect in an A site where A is disposed.

10. A thin film laminated on a substrate, A thin film comprising the ferromagnetic material according to any one of claims 1 to 9.

11. The thin film according to claim 10, The film thickness of the film is less than 1 μm.

12. 1. A method for producing a ferromagnetic material, comprising: the ferromagnetic material is composed of A and B, The A is (Al （１－ｘ） , M ｘ ) is composed of M is composed of one or more elements other than Al that belong to Group 3, Group 13, Group 14, or Group 15, x is equal to or greater than 0 and less than 1, The B is (N （１－ｙ） , R ｙ ) is composed of R is composed of one or more elements belonging to Group 16 or Group 17, y is greater than 0 and less than 1; The manufacturing method includes the following steps: In the substrate preparation step, a substrate is prepared, In the atmosphere adjustment step, the substrate is exposed to an atmosphere composed of a gas containing N and the R as elements, In the laminating step, the elements constituting A are released toward the substrate in the atmosphere, thereby producing the ferromagnetic material laminated on the substrate.

13. The manufacturing method according to claim 12, wherein R is O.

14. The manufacturing method according to claim 13, The gas is O ２ The method includes:

15. The manufacturing method according to claim 12, In the laminating step, the elements constituting A are released from a predetermined base material by sputtering or molecular beam epitaxy in the atmosphere, thereby laminating the ferromagnetic material on the substrate.

16. The manufacturing method according to claim 12, The method of claim 1 , wherein the ferromagnetic material is the ferromagnetic material of claim 1 .

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