Magnetic body, actuator, and sensor

Abstract

A magnetic body includes, in this order: a base material; a magnet film containing a hard magnetic material containing a rare earth R and a transition metal T, the rare earth R containing Sm, Nd, or Pr, and the transition metal T containing Co or Fe; and a soft magnetic film containing a soft magnetic material containing a rare earth R and a transition metal T.

Description

Technical Field

[0001] This invention relates to magnetic materials, actuators, and sensors. Background Technology

[0002] In recent years, there has been a pursuit of miniaturization or thinning of various devices that use magnetic materials, such as actuators and sensors. To this end, the magnetic materials used inside these devices also need to be miniaturized or thinned. Thin magnetic materials, because other components are arranged in their vertical direction, are sometimes magnetized in the thickness direction.

[0003] For example, Patent Document 1 discloses a magnet that has a yoke containing a soft magnetic material and a magnet containing a hard magnetic material formed on the main surface of the yoke, wherein the interface between the yoke and the magnet is concave-convex.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2022 / 045260 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] However, it is known that a magnetic field, known as the anti-magnetic field, is formed inside a magnet in the opposite direction to the magnetization. Moreover, the flatter the magnet is in the magnetization direction, that is, the thinner it is in the magnetization direction, the stronger its anti-magnetic field and the smaller its permeability. As a result, the operating point shifts towards the lower magnetic flux density side, and it is easily demagnetized, for example, by high temperature environments or the application of the anti-magnetic field.

[0009] From the perspective of suppressing the aforementioned demagnetization, the aim is to achieve a magnetic material with a large permeability while simultaneously achieving thinness.

[0010] The technical problem to be solved by the present invention is to provide a magnetic body with a large permeability coefficient, an actuator and a sensor comprising the above-mentioned magnetic body.

[0011] Means for solving technical problems

[0012] The present invention includes the following methods.

[0013] <1> A magnetic body comprising, in sequence: a substrate; a magnetic film comprising a hard magnetic body containing rare earth element R and transition metal T, wherein the rare earth element R contains Sm, Nd or Pr, and the transition metal T contains Co or Fe; and a soft magnetic film comprising the soft magnetic body containing the rare earth element R and the transition metal T.

[0014] <2> according to <1> The magnetic body, wherein the soft magnetic body comprises R2T7, RT3 or RT2.

[0015] <3> according to <1> or <2> The magnetic body, wherein the hard magnetic body comprises RT5 and R2T. 17 or RT 12 .

[0016] <4> according to <1> ~ <3> The magnetic body described in any one of the following statements, wherein the hard magnetic body comprises SmCo5 and Sm2Co. 17 、SmFe 12 or NdFe 12 .

[0017] <5> according to <1> ~ <4> The magnetic body according to any one of the following methods, wherein the thickness of the soft magnetic film is more than 1 μm and less than 50 μm.

[0018] <6> according to <1> ~ <5> The magnetic body according to any one of the following methods, wherein the thickness of the magnetic film is more than 10 μm and less than 200 μm.

[0019] <7> An actuator having <1> ~ <6> The magnetic body as described in any one of the following.

[0020] <8> A sensor that has <1> ~ <6> The magnetic body as described in any one of the following.

[0021] The effects of the invention

[0022] According to the present invention, it is possible to provide a magnetic body with a high permeability, an actuator comprising the magnetic body, and a sensor. Attached Figure Description

[0023] Figure 1 This is a schematic cross-sectional view of an SmCo-based magnetic material, which is an example of a magnetic material in this embodiment.

[0024] Figure 2 This is a schematic cross-sectional view of the magnetic body in the manufacturing method of the cylindrical magnetic body of this embodiment.

[0025] Figure 3 In the diagram, (a) is a schematic diagram of the axial cross-section of motor 100x, and (b) is a cross-sectional view perpendicular to the axis of (a).

[0026] Figure 4 This is an exploded perspective view showing a voice coil actuator as an example of this embodiment.

[0027] Figure 5 This is a cross-sectional view of the voice coil actuator 100y along the central axis AX of the coil portion 30y.

[0028] Figure 6 It is the cross section of the first magnetic body 10y and the second magnetic body 20y, which are perpendicular to the central axis AX.

[0029] Figure 7 It is a schematic diagram of a two-dimensional model.

[0030] Figure 8 The image is obtained by observing the magnetic body of Example 6-1 using a scanning electron microscope.

[0031] Figure 9 The image was obtained by observing the magnetic object of Comparative Example 1-1 using a scanning electron microscope.

[0032] Symbol Explanation

[0033] 10…substrate, 12…Co substrate (Co substrate), 20…magnetic film, 25…film containing Sm, 30…soft magnetic film, 52…laminar, 100…magnetic body, 300…magnetic body, 10x…rotor, 12x…ferromagnetic shaft, 12Ex…exposed portion, 14x…cylindrical magnetic body, 20x…stator, 22x…yoke, 23x…tooth, 24x…coil, 30x…container, 40x…bearing, 100x…motor, 100y, 101y…voice coil actuator, 10y…first magnetic body, 10ay… …(First magnetic body) outer peripheral surface, 20y…Second magnetic body, 20ay…(Second magnetic body) outer peripheral surface, 20by…(Second magnetic body) inner peripheral surface, 1y, 11y, 21y…Co layer, 2y, 12y, 22y…SmCo5 layer, 3y, 13y, 23y…Sm2Co7 layer, 30y…coil section, 31y…coil, 32y…winding frame, 32ay…upper cover section, 32by…main body section, 40y…bottom yoke, 50y…gap, 1001…measurement point of soft magnetic film, 1002…measurement point of magnetic film. Detailed Implementation

[0034] Hereinafter, a detailed description will be given of the method for carrying out the present invention (hereinafter referred to as "this embodiment").

[0035] Furthermore, the following embodiments are illustrative of the present invention, and the present invention is not limited to the following embodiments. The present invention can be implemented with appropriate modifications within its scope.

[0036] In this embodiment, the numerical range represented by “~” refers to the range in which the values ​​recorded before and after “~” are respectively the minimum and maximum values.

[0037] Within the numerical range recorded in this embodiment, the upper or lower limit value recorded within a certain numerical range can also be replaced by the upper or lower limit value of other numerical ranges recorded in different stages. Furthermore, within the numerical range described in this disclosure, the upper or lower limit value recorded within a certain numerical range can also be replaced by the value shown in the embodiment.

[0038] In this embodiment, a combination of two or more preferred methods is a more preferred method.

[0039] In this embodiment, in terms of the amount of each component, when there are multiple substances corresponding to each component, the total amount of multiple substances is represented unless otherwise specified.

[0040] Magnetic Materials

[0041] The magnetic body of this embodiment sequentially comprises: a substrate; a magnetic film comprising a hard magnetic body containing rare earth element R and transition metal T, wherein the rare earth element R contains Sm, Nd or Pr, and the transition metal T contains Co or Fe; and a soft magnetic film comprising a soft magnetic body containing rare earth element R and transition metal T.

[0042] The magnetic material of this embodiment increases its magnetic permeability by incorporating the above-described structure. In particular, the magnetic material of this embodiment can increase its magnetic permeability without increasing the thickness of the magnetic film itself.

[0043] In this embodiment, the magnetic material includes a soft magnetic film on the side of the magnetic film opposite to the substrate. This reduces the magnetic reluctance of the magnetic path originating from the N-pole surface of the magnetic film, passing outside the magnetic film, and returning to the S-pole surface. Therefore, the reverse magnetic field can be reduced without increasing the thickness of the magnetic film itself. As a result, the operating point shifts towards the hard magnetic flux density side, suppressing demagnetization.

[0044] <Magnetic membrane>

[0045] The magnetic material of this embodiment includes a magnetic film containing a hard magnetic material, which contains rare earth R containing Sm, Nd or Pr, and transition metal T containing Co or Fe.

[0046] Hard magnetic materials preferably contain RT5 and R2T. 17 or RT 12 More preferably, it contains RT5 or R2T 17 .

[0047] Below, R x T y A phase refers to an alloy or compound in which the ratio of element R to element T is x:y. R x T yAs long as the ratio of R element to T element is x:y, it is acceptable. For example, it can also contain 0 to 10% by mass of impurities (elements other than R and T elements).

[0048] Rare earth element R can also include rare earth elements other than Sm, Nd, and Pr. For example, rare earth element R can also include Sc, Y, or lanthanides.

[0049] Transition metal T does not contain rare earth elements.

[0050] Transition metal T may also include transition metals other than Co and Fe. For example, transition metal T may also include Ni.

[0051] Hard magnetic materials may also contain other elements besides the rare earth elements R and the transition metals T mentioned above.

[0052] Other elements that can be cited include N, Li, K, Cl, Mo, Ta, Nb, Ti, Ni, and Cr.

[0053] Hard magnetic materials preferably also contain nitrogen (N).

[0054] Hard magnetic materials are not particularly limited as long as they contain rare earth elements (R) containing Sm, Nd, or Pr and transition metals (T) containing Co or Fe; they can also be known alloys or compounds with hard magnetic properties. Examples include SmCo5, SmFe7, and SmFe... 12 ,Sm(Co,Fe)5,Sm(Fe,Co)7,Sm(Fe,Co) 12 Sm2Co 17 Sm2Fe 17 N3, Sm2 (Co, Fe) 17 Sm2 (Fe, Co) 17 N3, Sm5Fe 17 Sm5 (Fe, Co) 17 NdFe 12 Nd(Fe, Co) 12 PrFe 12 Pr2Fe 17 Pr5Fe 17 wait.

[0055] In the above, the hard magnetic material preferably contains SmCo5 and Sm2Co. 17 Sm2Fe 17 N3, SmFe 12 or NdFe 12 More preferably, it contains SmCo5 or Sm2Co 17 .

[0056] In this embodiment, the composition ratio of each element in the phase containing rare earth element R and transition metal T (e.g., R) is... x T y The ratio of R to T elements in a phase may not always be a stoichiometric ratio because various elements are added for purposes such as improving magnetic properties.

[0057] In this embodiment, as long as the composition ratio of each element in the phase containing rare earth element R and transition metal T has the corresponding crystal structure, the composition ratio of each element can also deviate from the stoichiometric ratio.

[0058] For example, as long as SmCo2 has a MgCu2-type crystal structure, the ratio of Sm to Co elements can deviate from the stoichiometric ratio.

[0059] For example, as long as SmCo5 has a CaCu5-type crystal structure, the ratio of Sm to Co elements can also deviate from the stoichiometric ratio.

[0060] For example, as long as SmFe7 has a TbCu7-type crystal structure, the ratio of Sm to Fe can also deviate from the stoichiometric ratio.

[0061] For example, as long as SmFe 12 With ThMn 12 If the crystal structure is of the type, the ratio of Sm to Fe elements can also deviate from the stoichiometric ratio.

[0062] For example, as long as Sm2Co 17 With Th2Zn 17 If the crystal structure is of the type, the ratio of Sm to Co elements can also deviate from the stoichiometric ratio.

[0063] For example, as long as Sm5Fe 17 Having Nd5Fe 17 If the crystal structure is of the type, the ratio of Sm to Fe elements can also deviate from the stoichiometric ratio.

[0064] For example, as long as Sm2Fe 17 N3 has Pr2Mn 17 C 1.77 If the crystal structure is of the type, the ratio of Sm, Fe, and N elements can also deviate from the stoichiometric ratio.

[0065] In this embodiment, the composition ratios of rare earth elements R, transition metals T, and other atoms were determined by energy dispersive X-ray spectroscopy (EDS).

[0066] Specifically, the magnetic material was embedded in resin, and the resulting sample was ground to expose a cross-section of the magnetic material from the resin. The cross-section was observed using SEM to determine the location of the magnetic film within the magnetic material. The approximate center of the magnetic film's thickness direction was used as the measurement location, and the composition ratio of rare-earth elements (R) to transition metals (T) was determined using EDS.

[0067] The content of hard magnetic material relative to the total area of ​​any cross section of the magnetic film can be, for example, more than 80%, more than 85%, more than 90%, more than 95%, or even 100%.

[0068] The thickness of the magnet film is preferably between 10 μm and 300 μm.

[0069] Because the thickness of the magnet film is more than 10 μm, the magnetic flux density of the magnet is excellent.

[0070] Based on the above viewpoints, the thickness of the magnet film is more preferably 25 μm or more, further preferably 40 μm or more, and even more preferably 70 μm or more.

[0071] By using a magnetic film with a thickness of less than 300 μm, the magnetic material can be made suitable for small devices.

[0072] Based on the above viewpoints, the thickness of the magnet film is more preferably 200 μm or less, further preferably 170 μm or less, and particularly preferably 130 μm or less.

[0073] The thickness of the magnet film can be determined by the following method: embedding the magnet in resin, grinding the resulting sample to expose the cross-section of the magnet from the resin, and observing the exposed cross-section of the magnet using a scanning electron microscope (SEM).

[0074] <Soft magnetic film>

[0075] The magnetic material of this embodiment includes a soft magnetic film containing a soft magnetic material, which contains the above-mentioned rare earth element R and the above-mentioned transition metal T.

[0076] Examples of soft magnetic materials include alloys and compounds containing rare earth elements (R) and transition metals (T). Sm₂Co₇ is an example of such an alloy.

[0077] Furthermore, the composition of rare earth elements (R) and transition metals (T) in soft magnetic materials differs from that in hard magnetic materials. That is, soft magnetic materials and hard magnetic materials each independently contain the aforementioned rare earth elements (R) and transition metals (T).

[0078] The soft magnetic material preferably contains R2T7, RT3 or RT2, and more preferably contains R2T7.

[0079] Soft magnetic materials may also contain, for example, SmCo2, SmCo3, SmFe2, SmFe3, Sm2Co7, and Sm2Fe. 17 Nd2Fe 17 Pr2Fe 17 Soft magnetic materials are not limited to these phases; they can also be phases other than those in known alloys or compounds (i.e., phases equivalent to hard magnetic materials) that contain rare-earth Rs containing Sm, Nd, or Pr and transition metals Ts containing Co or Fe, and that possess hard magnetism. In other words, soft magnetic materials can contain phases other than those found in hard magnetic materials.

[0080] In the above, the soft magnetic material preferably contains SmCo2, SmCo3, Sm2Co7, SmFe3, or Sm2Fe. 17 or Nd2Fe 17 More preferably, it contains SmCo2, SmCo3 or Sm2Co7.

[0081] The content of soft magnetic material in the soft magnetic film can be more than 80%, more than 85%, more than 90%, more than 95%, or even 100% relative to the total area of ​​any cross-section of the soft magnetic material.

[0082] The magnetic material in this embodiment may contain two or more soft magnetic films.

[0083] The magnetic body in this embodiment comprises a substrate, a magnetic film, and a soft magnetic film in sequence.

[0084] In this embodiment, when the magnetic body comprises two or more soft magnetic films, it is sufficient that at least one of the two or more soft magnetic films is disposed on the side of the magnetic film opposite to the substrate; it is not necessary for all the soft magnetic films to be disposed on the side of the magnetic film opposite to the substrate. For example, the magnetic body of this embodiment may further comprise a soft magnetic film between the substrate and the magnetic film, may further comprise a soft magnetic film between the magnetic film and the soft magnetic film, or may further comprise a soft magnetic film on the side of the soft magnetic film opposite to the magnetic film.

[0085] In this embodiment, the soft magnetic film included on the substrate side of the magnet film is also referred to as the substrate-side soft magnetic film, and the soft magnetic film included on the side of the magnet film opposite to the substrate is also referred to as the anti-substrate-side soft magnetic film.

[0086] Specifically, the magnetic body in this embodiment may sequentially include a substrate, a first soft magnetic film, a magnet film, and a second soft magnetic film; or it may sequentially include a substrate, a magnet film, a first soft magnetic film, and a second soft magnetic film; or it may sequentially include a substrate, a first soft magnetic film, a magnet film, a second soft magnetic film, and a third soft magnetic film.

[0087] Furthermore, in this embodiment, when the magnetic body comprises two or more soft magnetic films, the soft magnetic film arranged sequentially from the substrate side nth time is also referred to as the nth soft magnetic film.

[0088] The thickness of the soft magnetic film is preferably between 1 μm and 70 μm.

[0089] By using a soft magnetic film with a thickness of 1 μm or more, the magnetic permeability can be increased, which can suppress the demagnetization of the magnetic material.

[0090] Based on the above viewpoints, the thickness of the soft magnetic film is more preferably 3 μm or more.

[0091] By using a soft magnetic film with a thickness of less than 70 μm, the distance from the magnetic film to the surface of the magnetic body can be reduced, thereby significantly increasing the magnetic flux density on the surface of the magnetic body.

[0092] Based on the above viewpoints, the thickness of the soft magnetic film is more preferably 50 μm or less, further preferably 40 μm or less, particularly preferably 30 μm or less, and even more preferably 20 μm or less.

[0093] Furthermore, when the magnetic body comprises two or more soft magnetic films, the preferred range of the thickness of the aforementioned soft magnetic films refers to the total thickness of the soft magnetic films on the anti-substrate side, excluding the thickness of the soft magnetic films on the substrate side.

[0094] The thickness of the soft magnetic film can be determined by the following method: embedding a magnetic material in resin, grinding the resulting sample to expose the cross-section of the magnetic material from the resin, and observing the exposed cross-section of the magnetic material using a scanning electron microscope (SEM).

[0095] In this embodiment, it is preferable that the atomic ratio (R / T) of rare earth elements R to transition metal T in the soft magnetic material is greater than that of rare earth elements R to transition metal T in the hard magnetic material.

[0096] Furthermore, in the case where the magnetic body in this embodiment comprises two or more soft magnetic films, from the viewpoint of excellent magnetic permeability, it is preferable that the R / T in the soft magnetic body of the anti-substrate side soft magnetic film is greater than the R / T in the hard magnetic body.

[0097] Furthermore, when there are two or more anti-substrate side soft magnetic films, it is preferable that the R / T in the soft magnetic body of the anti-substrate side soft magnetic film away from the substrate side is greater than the R / T in the soft magnetic body of the anti-substrate side soft magnetic film close to the substrate side.

[0098] Furthermore, in the case where the magnetic body in this embodiment includes a substrate-side soft magnetic film, from the viewpoint of excellent magnetic permeability, it is preferable that the R / T in the soft magnetic body of the substrate-side soft magnetic film is smaller than the R / T in the hard magnetic body.

[0099] The ratio of the number of rare earth elements R to the number of transition metal elements T in soft and hard magnetic materials (R / T) is calculated by dividing the number of rare earth elements R by the number of transition metal elements T based on the chemical formula obtained from the composition ratio of the rare earth elements R, transition metal T and other atoms.

[0100] <Substrate>

[0101] The magnetic material in this embodiment includes a substrate.

[0102] Materials used as substrates include, for example, Co, Fe, Ni, Mo, Ta, Nb, FeCo, CoCr, CoCrMo, etc., with Co and Fe being preferred.

[0103] There are no particular restrictions on the shape of the substrate; examples include plate-shaped, cylindrical, and tubular shapes.

[0104] When the substrate is plate-shaped or cylindrical, there are no particular restrictions on its thickness, which can be selected appropriately according to the application. For example, the thickness of the substrate can be 1μm to 20mm, 10μm to 5mm, or 50μm to 1mm.

[0105] <SmCo-based magnetic materials>

[0106] Reference Figure 1 One embodiment of the magnetic body of this embodiment will be described.

[0107] Figure 1 This is a schematic cross-sectional view of an SmCo-based magnetic material, which is an example of a magnetic material in this embodiment.

[0108] like Figure 1 As shown, the SmCo-based magnetic material 100 (hereinafter also referred to as "magnetic material 100") of this embodiment includes a substrate 10, an SmCo5 film 20 formed on the substrate 10, and an Sm2Co7 film 30 formed on the SmCo5 film 20. In the magnetic material 100, the SmCo5 film 20 is a hard magnetic film, and the Sm2Co7 film 30 is a soft magnetic film.

[0109] SmCo5 membrane 20 contains SmCo5 as the main phase.

[0110] In this specification, "as the main phase" means having the largest area proportion in any cross-section of the membrane.

[0111] SmCo5 film 20 can also have phases different from SmCo5, such as other crystal phases and grain boundary phases.

[0112] The Sm2Co7 membrane 30 contains Sm2Co7 as the main phase.

[0113] Sm2Co7 film 30 can also have phases different from Sm2Co7, such as other crystal phases and grain boundary phases.

[0114] The crystal orientation [00L] of the SmCo5 film 20 is oriented in the thickness direction of the SmCo5 film, that is, in the direction perpendicular to the film surface A1. L is any natural number. L always refers to the same direction. For example, L is 2.

[0115] The crystal orientation [00L] of the SmCo5 film is oriented in the thickness direction of the SmCo5 film, which means that the degree of orientation as defined in equation (1) below is greater than 50%. This degree of orientation is based on the vector-corrected Lotgering method and represents the ratio of the sum of diffraction peaks based on the crystal orientation [00L] component to the sum of diffraction peaks based on the junction (hkl) of the SmCo5 film.

[0116]

[0117] From the viewpoint of further increasing the surface magnetic flux density of the magnetic body 100, the orientation degree is preferably 60% or more, more preferably 70% or more, and even more preferably 75% or more.

[0118] In equation (1), I represents the intensity of the diffraction peaks based on the crystal plane (hkl) when the Sm2Co5 film 20 is irradiated with X-rays. Each diffraction peak is attributed to any crystal plane represented by the Miller index. Examples of crystal planes of the SmCo5 film, in the case where 2θ is 30 to 60°, include the (002) plane, the (111) plane which is inclined relative to the (002) plane, and the (110) plane which is perpendicular to the (002) plane.

[0119] In equation (1), the numerator of the fraction on the right is the sum of the product of the intensity I of each diffraction peak of the SmCo5 film observed in the range of 2θ = 30 to 60° and the vector correction coefficient β assigned to the crystal plane of each peak.

[0120] The vector correction coefficient β is the cosine (cosθ) of the angle θ formed by the (00L) plane, which serves as the reference plane, and each crystal plane (hkl). This value varies depending on the crystal plane (hkl).

[0121] On the other hand, the denominator of the fraction on the right is the sum of the intensities I of each diffraction peak of the SmCo5 film in the range of 2θ = 30 to 60°.

[0122] The shape of the magnetic body 100 is not particularly limited and can be appropriately set according to the application. The shape of the magnetic body 100 viewed from the Z-axis direction can be, for example, a square, a rectangle, or a circle. When the magnetic body 100 is square when viewed from the Z-axis direction, the length of one side can be, for example, 0.1 to 100 mm. When the magnetic body 100 is rectangular when viewed from the Z-axis direction, the length of its long side can be, for example, 1 to 100 mm, and the length of its short side can be, for example, 0.1 to 50 mm. When the magnetic body 100 is circular when viewed from the Z-axis direction, its diameter can be, for example, 0.1 to 50 mm.

[0123] Manufacturing Method of SmCo-based Magnetic Materials

[0124] An example of a method for manufacturing a magnetic body according to this embodiment will be described in detail.

[0125] The method for manufacturing the magnetic body in this embodiment may include, for example, the following steps: a reaction diffusion step in which a film 25 containing Sm is formed on the Co substrate 12 by immersing it in a bath containing an Sm source and by reaction diffusion; and a step in heating the resulting laminate 52.

[0126] Figure 2 This is a schematic cross-sectional view of the method for manufacturing the magnetic body according to this embodiment. In the reaction diffusion process, the magnetic body is manufactured by reaction diffusion... Figure 2 A film 25 containing Sm is formed on the Co substrate 12 shown in (a), resulting in Figure 2 The laminate 52 shown in (b) has a Co substrate 12 and a film 25 containing Sm.

[0127] The Sm-containing membrane 25 preferably contains an Sm-containing material as the main phase.

[0128] Examples of materials containing Sm include Sm, SmCo2, SmCo3, Sm2Co7, Sm3Co, and Sm5Co2. For instance, SmCo2 is an alloy of Sm and Co with a MgCu2-type crystal structure.

[0129] The film 25 containing Sm can also have a crystalline phase (heterogeneous phase) or grain boundaries that are different from the main phase. The proportion of the main phase can be, for example, 50% or more by mass, 70% or more by mass, or 90% or more by mass.

[0130] In the reactive diffusion process, by impregnating the Co substrate 12 in a bath containing an Sm source, reactive diffusion occurs between the Sm source dispersed in the bath on the main surface of the Co substrate 12 and the Co substrate 12, thereby forming an Sm-containing film 25 on the Co substrate 12.

[0131] The bath in the reaction diffusion process can be a molten salt of an inorganic salt other than an Sm source.

[0132] Examples of Sm sources include metallic Sm and Sm alloys. A single Sm source can be used, or two or more sources can be used in combination.

[0133] Inorganic salts other than Sm sources include, for example, KCl, LiCl, and NaCl. These inorganic salts can be used alone or in combination of two or more.

[0134] Based on the total number of moles of Sm source and inorganic salts other than Sm source contained in the bath, the proportion of Sm source in Sm source and inorganic salts other than Sm source can be, for example, 0.2 to 6 mol / L.

[0135] The bath can be adjusted, for example, by drying the inorganic salt to dehydrate it, then heating it to the reaction diffusion temperature described later to melt the inorganic salt, and then adding an Sm source to the molten inorganic salt.

[0136] The reaction diffusion temperature in the reaction diffusion process is not particularly limited as long as it is above the melting temperature of the inorganic salt. From the viewpoint of effectively forming the Sm-containing film 25, it is preferably 400°C or higher, more preferably 500°C or higher, and even more preferably 600°C or higher. Here, the reaction diffusion temperature refers to the temperature of the bath during the reaction diffusion process.

[0137] As long as a film 25 containing Sm of the required thickness can be formed, the reaction diffusion time of the reaction diffusion process can be appropriately changed according to the reaction diffusion temperature and the molar concentration of the Sm source in the bath. In addition, from the point of view of efficiency, it is not necessary to set it to a longer time than necessary, for example, it can be 1 hour to 48 hours.

[0138] There are no particular restrictions on the atmosphere of the reaction diffusion process, but from the viewpoint of suppressing oxidation, an inert gas atmosphere is preferred. Examples of inert gases include Ar and N2.

[0139] The resulting laminate 52 can be cleaned before the heating process described later. There are no particular limitations on the cleaning method; for example, organic solvents such as ethylene glycol and water can be used.

[0140] In the heating process, the laminate 52 is heated to a holding temperature and then cooled. As a result, Sm-containing materials such as SmCo2 react with Co to form a soft magnetic film 30 such as an Sm2Co7 film and a magnetic film 20 such as an SmCo5 film with crystal orientation [00L] along the thickness direction of the film, from the Co substrate 12 and the Sm-containing film 25.

[0141] The heating rate during the heating process is not particularly limited, and can be, for example, 0.1 to 100 °C / second. Since the surface magnetic flux density of the magnetic body 300 is further increased, the holding temperature is preferably 800 °C or higher, more preferably 850 °C or higher, and even more preferably 900 °C or higher. Since the surface magnetic flux density of the magnetic body 300 is further increased, the cooling rate is preferably 5 °C / second or higher, more preferably 10 °C / second or higher, and even more preferably 20 °C / second or higher.

[0142] The holding time during the heating process is preferably more than 1 hour and less than 20 hours.

[0143] From the viewpoint that it is easier to form a soft magnetic film, the retention time is preferably less than 15 hours, and more preferably less than 12 hours.

[0144] There are no particular restrictions on the atmosphere of the heating process, but from the viewpoint of suppressing oxidation, an inert gas atmosphere is preferred. Examples of inert gases include Ar and N2.

[0145] The reaction diffusion process and the heating process are preferably performed in two stages. Specifically, it is preferable to perform the first heating process after the first reaction diffusion process, followed by the second reaction diffusion process and the second heating process. The second reaction diffusion process can be performed under the same conditions as the first reaction diffusion process, but it can also be performed for a shorter time. Through the second reaction diffusion process, a film 25 containing Sm is formed on the surface of the magnetic film 20. Therefore, the soft magnetic film 30 can be easily formed through the second heating process. In the second heating process, it is preferable to make the holding time shorter than that in the first heating process.

[0146] After the reaction diffusion process, the magnetic film 20 can also be nitrided by heating the magnetic material in a nitrogen atmosphere. Examples of nitrogen atmospheres include ammonia, a mixture of ammonia and hydrogen, nitrogen, and a mixture of nitrogen and hydrogen. Using ammonia allows for nitriding of the magnetic material in a short time. The gas flow rate can be appropriately selected based on the type of gas and the amount of sample. For example, the gas flow rate can be 10 mL / min or more, 50 mL / min or more, or 200 mL / min or more. The heating temperature is preferably 300°C or higher and 600°C or lower, and the heating time is preferably 1 hour to 60 hours.

[0147] In the reactive diffusion process, Sm2Fe can be manufactured by changing the Co substrate 12 to the Fe substrate 12. 17 Magnetic film. Further, by applying the above conditions to Sm2Fe... 17 Nitriding of magnetic films can yield Sm2Fe with high magnetic properties. 17 N3 magnetic membrane.

[0148] "use"

[0149] There are no particular limitations on the application of the magnetic material 200, but due to its high permeability, it can be used even in environments that generate large counter-magnetic fields or high temperatures, making it suitable for applications such as small devices. Examples of small devices include actuators (especially micro motors) and sensors.

[0150] <Actuator>

[0151] The actuator of this embodiment includes the magnetic body of this embodiment.

[0152] The following uses Figure 3 An electric motor will be described as an example of an actuator in this embodiment.

[0153] Figure 3 (a) is a schematic diagram of the axial cross-section of motor 100x, and (b) is a cross-sectional view perpendicular to the axis of (a).

[0154] The electric motor 100x has a rotor 10x, a stator 20x, and a capacitor 30x. The stator 20x is arranged to surround the outer peripheral surface of a cylindrical magnetic body 14x of the rotor 10x and has a cylindrical shape. Figure 3 As shown in (b), the stator 20x can have a yoke 22x, teeth 23x, and coils 24x. The specific structures of the yoke 22x, teeth 23x, and coils 24x of the stator 20x are not limited, and various structures can be adopted. For example, as shown... Figure 3 As shown, the stator 20x has a magnetic yoke 22x and a coil 24x, and may also be toothless. Furthermore, the coil 24x can be constructed using a coreless winding with a cylindrical shape or a flexible printed circuit board. Additionally, the material of the magnetic yoke 22x can be made of a soft magnetic material to increase torque, but by making it a non-magnetic material, the magnetic attraction between the rotor and stator can be reduced, thus also reducing friction.

[0155] The container 30x has a cylindrical shape that covers the outer periphery of the stator 20x. The material of the container 30x is not particularly limited, and for example, austenitic stainless steel or copper as non-magnetic materials, and ferrite or martensitic stainless steel, electromagnetic steel sheet, FeNi, Ni, etc. as magnetic materials can be used.

[0156] The outer diameter d3x of container 30x can be set to less than 3mm.

[0157] The distance between the outer circumferential surface of the cylindrical magnetic body 14x of the rotor 10x and the inner circumferential surface of the stator 20x can be set to 0.01 to 0.5 mm.

[0158] The exposed portion 12Ex of shaft 12x can be supported by bearing 40x. Bearing 40x is not particularly limited and various bearings, such as sliding bearings, can be used.

[0159] The rotor according to this embodiment has a cylindrical magnetic body 14x, so there are no seams on the magnetic body. Even if the rotor 10x is miniaturized, the volume ratio of the magnetic body can be easily increased. Because the cylindrical magnetic body 14x has a large permeability, the magnet is difficult to demagnetize even when a large counter-magnetic field is generated from the coil 24x. Therefore, it is easy to apply a large current to the coil 24x, thereby increasing the torque of the motor.

[0160] Furthermore, since there is no protective film or adhesive layer for the magnetic material such as resin or oxide film between the cylindrical magnetic body 14x and the shaft 12x, the proportion of non-magnetic layers in the rotor can be reduced and the proportion of magnetic material can be increased, making it easier to increase the torque of the motor.

[0161] In addition, if 1≤Lx / d1x, even the small diameter can be made into a long axis, thus making it easier to increase the torque of the motor.

[0162] Furthermore, if the surface roughness of the outer peripheral surface of the cylindrical magnetic body 14x is small, or the variation coefficient of the thickness of the cylindrical magnetic body 14x is below a certain value, the distance between the outer peripheral surface of the cylindrical magnetic body of the rotor and the inner surface of the stator can be reduced, thus further increasing the driving torque.

[0163] Furthermore, if there are exposed portions 12Ex at both ends of the shaft 12x, these two portions can be supported by bearings 40x. When a cylindrical magnetic body is present in the portion supported by bearings 40x, electromagnetic forces that hinder driving may sometimes be generated due to rotation, but by supporting the exposed portions 12Ex by bearings 40x, the excess electromagnetic force is reduced. If bearings 40x are sliding bearings, miniaturization is possible.

[0164] In addition, when the coil 24x is a coreless winding with a cylindrical shape or a flexible printed circuit board, it is suitable for miniaturization.

[0165] Furthermore, when the stator 20x has a structure with teeth 23x, the rotational torque increases due to the increase in magnetic flux linked with the coil 24x.

[0166] The electric motor in this embodiment is not limited to the example described above, and can be modified in various ways.

[0167] For example, in the above example, the ferromagnetic shaft 12x and the cylindrical magnetic body 14x are in direct contact without a non-magnetic layer, but a non-magnetic layer of about 5 μm or less (such as an oxide layer, resin layer, adhesive layer, etc.) may be provided.

[0168] Furthermore, the shape is not limited to the fine shape of the shaft 12x or the cylindrical magnetic body 14x; various shapes can be adopted depending on the object.

[0169] Furthermore, by configuring the motor 100x to be cut radially from the center, it can be used as a linear actuator. Moreover, by offsetting the position of the coil 24x or adding an additional coil in this state, it can be used as an actuator that drives in the outward direction.

[0170] The following uses Figures 4-6 A voice coil actuator, which is an example of an actuator in this embodiment, will be described.

[0171] Figure 4 This is an exploded perspective view showing a voice coil actuator as an example of this embodiment.

[0172] like Figure 4 As shown, the voice coil actuator 100y of this embodiment has a first magnetic body 10y, a second magnetic body 20y, and a coil portion 30y.

[0173] The first magnetic body 10y and the second magnetic body 20y are elements constituting the magnetic circuit of the voice coil actuator 100y. In addition to the first magnetic body 10y and the second magnetic body 20y, the voice coil actuator 100y may also have a bottom magnetic yoke 40y as a constituent element of the magnetic circuit.

[0174] In addition, the voice coil actuator 100y has the following features: Figure 4 In addition to the magnetic circuit (10y, 20y, 40y) and coil section 30y shown, it may also include various sensors such as external (container), magnetic sensor or displacement sensor, and driven objects (such as magnetic head, lens, vibrating plate, etc.).

[0175] In the voice coil actuator 100y, the magnetic circuit side can be fixed while driving the coil portion 30y. Alternatively, the coil portion 30y can be fixed while driving the first magnetic body 10y and / or the second magnetic body 20y constituting the magnetic circuit. That is, the voice coil actuator 100y can be a movable coil or a movable magnetic body. Furthermore, the method of fixing the magnetic circuit or the coil portion 30y is not particularly limited. For example, the voice coil actuator 100y can have an outer casing (container) not shown, and the magnetic circuit or the coil portion 30y can be assembled and fixed to this outer casing.

[0176] Figure 5 This is a cross-sectional view of the voice coil actuator 100y along the central axis AX of the coil section 30y.

[0177] Figure 6 It is the cross section of the first magnetic body 10y and the second magnetic body 20y, which are perpendicular to the central axis AX.

[0178] Figure 5 and Figure 6 The central axis AX shown is an imaginary line that runs along the inner circumferential surface of the coil portion 30y and through the center of the region (inner coil region) surrounded by the inner circumferential surface of the coil portion 30y. Furthermore, in each figure, the Z-axis is parallel to the central axis AX, and the X-axis, Y-axis, and Z-axis are perpendicular to each other.

[0179] like Figure 5 and Figure 6 As shown, the first magnetic body 10y is located at the center of the voice coil actuator 100y. In other words, the first magnetic body 10y is disposed in the inner region of the coil through which the central axis AX of the coil portion 30y passes. The first magnetic body 10y preferably has a cylindrical shape (see reference). Figure 4 However, the shape of the first magnetic body 10y is not necessarily limited. For example, the first magnetic body 10y may also have a prism shape, a cylindrical shape, or a square shape.

[0180] The size of the first magnetic body 10y is not particularly limited and can be appropriately determined according to the application of the voice coil actuator 100y. From the viewpoint of miniaturizing the voice coil actuator 100y, the diameter d1y (outer diameter) of the first magnetic body 10y is preferably 0.5 mm to 4 mm, and the length L1y in the Z-axis direction of the first magnetic body 10y is preferably 1 mm to 20 mm. Furthermore, when the first magnetic body 10y has a cylindrical shape, the inner diameter of the first magnetic body 10y is preferably, for example, 0.2 mm to 3 mm, and the thickness of the first magnetic body 10y is preferably 0.1 mm to 1.9 mm.

[0181] like Figure 5 and Figure 6 As shown, the second magnetic body 20y is located outside the first magnetic body 10y and the coil portion 30y in a direction parallel to the XY plane, and is opposite to the first magnetic body 10y via a gap 50y. The second magnetic body 20y preferably has a cylindrical shape (see reference). Figure 4 ),like Figure 5 and Figure 6 As shown, the inner circumferential surface 20by of the second magnetic body 20y, which is cylindrical, faces the outer circumferential surface 10ay of the first magnetic body 10y via a gap 50y. However, the shape of the second magnetic body 20y is not necessarily limited; for example, the second magnetic body 20y may also have a rectangular shape. Alternatively, the second magnetic body 20y may also have a pair of plate shapes sandwiched between the first magnetic body 10y and the gap 50y.

[0182] The size of the second magnetic body 20y is not particularly limited and can be appropriately determined according to the application of the voice coil actuator 100y. When the second magnetic body 20y has a cylindrical shape, from the viewpoint of miniaturizing the voice coil actuator 100y, the outer diameter d2ay of the second magnetic body 20y is preferably 1 mm or more and 6 mm or less, and the inner diameter d2by of the second magnetic body 20y is preferably 0.8 mm or more and 5 mm or less. The thickness of the second magnetic body 20y is expressed as (d2ay - d2by) / 2, and is preferably, for example, 0.1 mm or more and 2 mm or less. Furthermore, the length L2y of the second magnetic body 20y in the Z-axis direction can also be, for example, 1 mm or more and 20 mm or less.

[0183] The width t5y of the gap 50y between the first magnetic body 10y and the second magnetic body 20y is represented by (d2by-d1y) / 2, and is preferably 0.1mm or more and 1mm or less. Furthermore, the ratio (d2by / d1y) of the inner diameter d2by of the second magnetic body 20y to the diameter d1y of the first magnetic body 10y is preferably, for example, 1.2 times or more and 3 times or less. The ratio (L2y / L1y) of the length L2y of the second magnetic body to the length L1y of the first magnetic body 10y is not particularly limited, and can be, for example, 0.5 times or more and 3 times or less.

[0184] As described above, the bottom yoke 40y is an essential component of the magnetic circuit in the voice coil actuator 100y, for example, as Figure 4 As shown, it can also be in the shape of a circular plate. Alternatively, the bottom magnetic yoke 40y can be a plate with a roughly rectangular or polygonal shape when viewed from above, or it can be in the shape of a ring. The thickness of the bottom magnetic yoke 40y in the Z-axis direction is not particularly limited, for example, it can be 0.5mm to 2mm. The bottom magnetic yoke 40y can be made of soft magnetic materials such as Co or SS400, and the material of the bottom magnetic yoke 40y is not particularly limited.

[0185] The first magnetic body 10y and / or the second magnetic body 20y can also be attached to the upper surface of the bottom magnetic yoke 40y in the Z-axis direction using an adhesive or the like. Alternatively, a gap can be provided between the bottom magnetic yoke 40y and the other magnetic bodies (the first magnetic body 10y and / or the second magnetic body 20y). Furthermore, the bottom magnetic yoke 40y can also be integrated with the substrate of the first magnetic body 10y or the substrate of the second magnetic body 20y.

[0186] Figures 4-6The illustrated coil portion 30y includes a coil 31y and a winding frame 32y made of non-magnetic material. The winding frame 32y integrally comprises a circular plate-shaped upper cover portion 32ay and a cylindrical body portion 32by, and the coil 31y is formed by winding conductive wire around the outer peripheral surface of the body portion 32by. The winding method and number of turns of the conductive wire in the coil 31y are not particularly limited. Furthermore, the shape and size of the winding frame 32y are not particularly limited. For example, the winding frame 32y may only have a cylindrical body portion 32by without the upper cover portion 32ay. Alternatively, the body portion 32by of the winding frame 32y may also have a square tube shape.

[0187] The region surrounded by the inner circumferential surface of the main body portion 32by, where the coil 31y is formed, is the inner region of the coil, such as... Figure 5 and Figure 6 As shown, a first magnetic body 10y is inserted into the inner region of the coil. In other words, the coil 31y is positioned in the gap 50y between the first magnetic body 10y and the second magnetic body 20y.

[0188] As described above, the coil portion 30y in the voice coil actuator 100y includes a coil 31y and a winding frame 32y, but the coil 31y is not limited to a structure in which conductive wire is wound on the winding frame 32y. For example, as the coil portion 30y of the voice coil actuator 100y, a flexible printed circuit board with printed coil wiring can also be used. Alternatively, as the coil portion 30y of the voice coil actuator 100y, a molded coil with windings sealed by resins such as epoxy resin or polyester resin can also be used. Alternatively, the coil portion 30y can be formed using self-fusion type conductive wire. As the coil portion 30y, even when a coil composed of a flexible printed circuit board, a molded coil, or self-fusion type conductive wire is used, the coil portion only needs to be positioned in the gap 50y between the first magnetic body 10y and the second magnetic body 20y.

[0189] In the voice coil actuator 100y of this embodiment, such as Figure 5 and Figure 6 As shown, the first magnetic body 10y and the second magnetic body 20y each have a multilayer structure.

[0190] The multilayer structure of the first magnetic body 10y and the second magnetic body 20y may include, for example, a Co layer 1y, an SmCo5 layer 2y, and an Sm2Co7 layer 3y.

[0191] exist Figure 5 and Figure 6 In the text, the layers in the multilayer structure of the first magnetic body 10y are referred to as "Co layer 11y, SmCo5 layer 12y, and Sm2Co7 layer 13y". Similarly, the layers in the multilayer structure of the second magnetic body 20y are referred to as "Co layer 21y, SmCo5 layer 22y, and Sm2Co7 layer 23y".

[0192] When the first magnetic body 10y has a cylindrical shape, the average diameter (outer diameter) d11y of the Co layer 11y, which serves as the substrate in the magnetic body of this embodiment, is not particularly limited, but from the viewpoint of miniaturizing the voice coil actuator 100y, it is preferably 0.5 mm or more and 4 mm or less. Furthermore, when the first magnetic body 10y has a cylindrical shape, the average thickness of the Co layer 11y is preferably 0.1 mm or more and 1.8 mm or less.

[0193] The average thickness t12y of the SmCo5 layer 12y in the first magnetic body 10y is not particularly limited, and can be within the preferred range of the thickness of the magnetic film in the above-mentioned <magnetic film>.

[0194] The average thickness t13y of the Sm2Co7 layer 13y in the first magnetic body 10y is not particularly limited, and can be within the preferred range of the thickness of the soft magnetic film in the above-mentioned <soft magnetic film>.

[0195] The average thickness t21y of the Co layer 21y in the second magnetic body 20y is not particularly limited, and can be within the preferred range of the thickness of the substrate in the above <substrate>.

[0196] The average thickness t22y of the SmCo5 layer 22y in the second magnetic body 20y is not particularly limited, and can be within the preferred range of the thickness of the magnetic film in the above-mentioned <magnetic film>.

[0197] The average thickness t23y of the Sm2Co7 layer 23y in the second magnetic body 20y is not particularly limited, and can be within the preferred range of the thickness of the soft magnetic film in the above-mentioned <soft magnetic film>.

[0198] According to the voice coil actuator of this embodiment, since the permeability of the SmCo5 layer 2y in the multilayer structure of the first magnetic body 10y and the second magnetic body 20y is large, the magnet is not easily demagnetized even when a large counter-magnetic field is generated from the coil 31y. Therefore, it is easy to apply a large current to the coil 31y, further increasing the driving force of the voice coil actuator.

[0199] <Sensors>

[0200] The sensor of this embodiment has a magnetic body as described in this embodiment.

[0201] The sensor in this embodiment can be, for example, a magnetic sensor that detects rotational and translational position information as changes in the magnetic field.

[0202] The sensor in this embodiment can preferably be used, for example, as a magnetic encoder.

[0203] A magnetic encoder can detect position information as changes in the magnetic field, convert it into an electrical signal, and output it.

[0204] According to the sensor of this embodiment, because the magnetic permeability of the magnetic film is large, the magnet is not easily demagnetized even when the temperature rises. Therefore, it can be used even in high-temperature environments.

[0205] Example

[0206] The present invention will be further described in detail below through embodiments, but the present invention is not limited to the following embodiments.

[0207] [Examples 1-13, Comparative Examples 1-4]

[0208] For Examples 1-13 and Comparative Examples 1-4, simulations were performed using the following method.

[0209] First, a two-dimensional model in the XY direction was constructed using electromagnetic field analysis software (JSOL JMAG-Designer Ver.22).

[0210] A schematic diagram of the above two-dimensional model is shown in... Figure 7 .

[0211] like Figure 7 As shown, the two-dimensional model sequentially includes a substrate 10 with a thickness of 200 μm, a magnetic film 20 with a thickness of 42 μm, and a soft magnetic film 30 with a thickness t as listed in Table 1. The width of each layer in the X direction is 500 μm, and they are arranged in a non-offset overlapping configuration. Furthermore, the magnetic film is magnetized with the positive Y direction as its N pole.

[0212] In each embodiment and comparative example, the types of hard magnetic materials in the substrate and the soft magnetic materials in the soft magnetic film, as well as the thickness of the soft magnetic film, were varied as shown in Table 1, and the magnetic flux flow of the resulting model was calculated. Based on the calculated magnetic flux distribution, the operating point at the center of the magnet was derived, and the permeability was calculated.

[0213] In addition, using the permeability obtained above, the permeability (%) is calculated by the following formula.

[0214] Permeability (%) = (Permeability of each embodiment / Permeability used as a reference) × 100

[0215] Furthermore, the permeability coefficient used as the reference for Examples 1 to 10 is the permeability coefficient of Comparative Example 1. The permeability coefficient used as the reference for Example 11 is the permeability coefficient of Comparative Example 2. The permeability coefficient used as the reference for Example 12 is the permeability coefficient of Comparative Example 3. The permeability coefficient used as the reference for Example 13 is the permeability coefficient of Comparative Example 4.

[0216] [Table 1]

[0217]

[0218] As shown in Table 1, Examples 1 to 10 using the following magnetic materials have a larger permeability compared to Comparative Example 1 which does not contain a soft magnetic film. The magnetic materials described above sequentially include: a substrate; a magnetic film containing a hard magnetic material containing rare earth element R and transition metal T, wherein the rare earth element R contains Sm, Nd or Pr, and the transition metal T contains Co or Fe; and a soft magnetic film containing a soft magnetic material containing rare earth element R and transition metal T.

[0219] Similarly, Example 11 has a larger permeability than Comparative Example 2 which does not contain a soft magnetic film, Example 12 has a larger permeability than Comparative Example 3 which does not contain a soft magnetic film, and Example 13 has a larger permeability than Comparative Example 4 which does not contain a soft magnetic film.

[0220] [Example 6-1]

[0221] <Manufacturing of Magnetic Materials>

[0222] A magnetic body equivalent to the simulated magnetic body of Example 6 was manufactured by the following method.

[0223] (First reaction diffusion process)

[0224] Prepare LiCl and dehydrate it by drying. Melt the dehydrated LiCl in a Mo metal container at 700°C using an external heater. Add an Sm source (a rare-earth R source) to the molten LiCl. The Sm source is added at a concentration of 1 mol / L of rare-earth R relative to 100 moles of LiCl. Next, immerse a Co substrate in the molten LiCl. The substrate is pre-cleaned with acetone. The reaction diffusion temperature is set to 700°C, and the reaction diffusion time is set to 9 hours. Through the reaction diffusion process, a laminate with an SmCo2 film formed on the Co substrate is obtained.

[0225] (First heating process)

[0226] The resulting laminate was heated at 1050°C for 12 hours without applying a magnetic field. Afterward, the laminate was cooled without applying a magnetic field, thus obtaining a magnetic material.

[0227] The heating rate is set to 0.15℃ / second, and the cooling rate is set to 20℃ / second. The atmosphere for the heating process is set to Ar.

[0228] (Second reaction diffusion process)

[0229] For the obtained magnetic material, except that the reaction diffusion time is set to 1 hour, the second reaction diffusion process is carried out under the same conditions as the first reaction diffusion process.

[0230] (Second heating process)

[0231] For the obtained magnetic material, except that the holding time is set to 30 minutes, a second heating process is performed under the same conditions as the first heating process.

[0232] The structure of the obtained magnetic material was confirmed by X-ray diffraction and energy-dispersive X-ray analysis to be that Sm2CO was sequentially formed on a Co substrate. 17 The structure of membranes, SmCo5 membranes and Sm2Co7 membranes.

[0233] Images obtained by observing the magnetic material of Example 6-1 using a scanning electron microscope (manufactured by Hitachi High-Tech Corporation, trade name SU5000) are shown below. Figure 8 .

[0234] in addition, Figure 8 The EDS analysis values ​​(at%) at measurement point 1001 of the soft magnetic film and measurement point 1002 of the magnet film are shown in Table 2.

[0235] [Table 2]

[0236]

[0237] [Comparative Example 1-1]

[0238] <Manufacturing of Magnetic Materials>

[0239] Except for omitting the second reaction diffusion step and the second heating step, a magnetic body equivalent to the simulated magnetic body of Comparative Example 1 was manufactured under the same conditions as the manufacturing method of Example 6-1.

[0240] Images obtained by observing the magnetic object of Comparative Example 1-1 using a scanning electron microscope are shown below. Figure 9 .

[0241] [Example 11-1]

[0242] <Manufacturing of Magnetic Materials>

[0243] Except for changing the heating and holding temperature in the first heating step to 1100°C, a magnetic body equivalent to the simulated magnetic body of Example 11 was manufactured under the same conditions as the manufacturing method of Example 6-1.

[0244] [Example 12-1]

[0245] <Manufacturing of Magnetic Materials>

[0246] Except for changing the substrate used in the first reaction diffusion step from Co to Fe and changing the heating time in the first heating step to 18 hours, a magnetic body equivalent to the simulated magnetic body of Example 12 was manufactured under the same conditions as the manufacturing method of Example 11-1.

[0247] [Example 13-1]

[0248] <Manufacturing of Magnetic Materials>

[0249] Except for changing the rare earth R source added in the first and second reaction diffusion steps from Sm to Nd; changing the reaction diffusion temperature to 750°C; and changing the heating time in the first heating step to 24 hours, a magnetic body equivalent to the simulated magnetic body of Example 13 was manufactured under the same conditions as the manufacturing method of Example 12-1.

[0250] <Evaluation>

[0251] (Thickness measurement of soft magnetic films, magnetic films and magnetic materials)

[0252] The obtained flat magnetic material was embedded in resin. By grinding a portion of the resin, a section of the magnetic material parallel to the easy magnetization axis was exposed. The exposed section was observed using a scanning electron microscope (Hitachi High-Tech Corporation, trade name SU5000), and the thicknesses of the soft magnetic film, the magnetic film, and the substrate were measured. At this point, the magnification was adjusted so that the entire film and the magnetic material being measured were included in the field of view.

[0253] In Example 6-1, the thickness of the soft magnetic film is 17 μm, the thickness of the magnet film is 42 μm, and the thickness of the substrate is 200 μm.

[0254] In Comparative Example 1-1, no observable soft magnetic film was found; the thickness of the magnet film was 42 μm; and the thickness of the substrate was 200 μm.

[0255] In Example 11-1, the thickness of the soft magnetic film is 10 μm, the thickness of the magnet film is 42 μm, and the thickness of the substrate is 200 μm.

[0256] In Example 12-1, the thickness of the soft magnetic film is 10 μm, the thickness of the magnet film is 42 μm, and the thickness of the substrate is 200 μm.

[0257] In Example 13-1, the thickness of the soft magnetic film is 10 μm, the thickness of the magnet film is 42 μm, and the thickness of the substrate is 200 μm.

[0258] (Evaluation of demagnetization characteristics)

[0259] A magnetic field of 6T was applied to the magnetic films of Examples 6-1 and 1-1 to magnetize the magnetic material along the thickness direction of the film. Then, the magnetic material was attached to the bottom surface of a 2cm square stainless steel (SUS430) cube, and a heating test was conducted using an oven (manufactured by YamatoScientific Co., Ltd., model DH650). However, the bottom surface of the stainless steel cube was suspended in the oven. The temperature at which the magnetic material demagnetized was measured as the temperature at which it fell from the stainless steel cube. That is, the magnetic material that fell at a lower temperature was evaluated as easily demagnetized. The results are shown in Table 3.

[0260] [Table 3]

[0261]

[0262] As shown in Table 3, Example 6-1, which uses the following magnetic material, has a higher drop temperature and is less prone to demagnetization compared to Comparative Example 1-1, which does not contain a soft magnetic film. The magnetic material comprises, in sequence: a substrate; a magnetic film containing a hard magnetic material containing rare earth element R and transition metal T, wherein the rare earth element R contains Sm, Nd, or Pr, and the transition metal T contains Co or Fe; and a soft magnetic film containing a soft magnetic material containing rare earth element R and transition metal T.

[0263] The entire disclosure of Japanese Patent Application No. 2023-177252, filed on October 13, 2023, is incorporated herein by reference. All documents, patent applications, and technical specifications set forth in this specification are incorporated herein by reference to the same extent as if each document, patent application, and technical standard were specifically and individually indicated to be incorporated herein by reference.

Claims

1. A magnetic body, wherein, The magnetic body comprises, in sequence: Substrate; A magnetic film comprising a hard magnetic material containing rare-earth element R and transition metal T, wherein the rare-earth element R comprises Sm, Nd, or Pr, and the transition metal T comprises Co or Fe; and A soft magnetic film comprising a soft magnetic material containing the rare earth element R and the transition metal T.

2. The magnetic body according to claim 1, wherein, The soft magnetic material includes R2T7, RT3, or RT2.

3. The magnetic body according to claim 1 or 2, wherein, The hard magnetic material includes RT5 and R2T. 17 or RT 12 .

4. The magnetic body according to claim 1 or 2, wherein, The hard magnetic material contains SmCo5 and Sm2Co. 17 、SmFe 12 or NdFe 12 .

5. The magnetic body according to claim 1 or 2, wherein, The thickness of the soft magnetic film is more than 1 μm and less than 50 μm.

6. The magnetic body according to claim 1 or 2, wherein, The thickness of the magnet film is between 10 μm and 300 μm.

7. An actuator, wherein, The actuator comprises the magnetic body as described in claim 1.

8. A sensor, wherein, The sensor comprises the magnetic material as described in claim 1.

Images