JP2010062484A - Core shell type magnetic material, device apparatus, and antenna assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a core shell type magnetic material which has superior characteristics in a high frequency band, especially, in a GHz band. <P>SOLUTION: The core shell type magnetic material includes amorphous magnetic metal particles containing at least one magnetic metal selected from a group of Fe, Co and Ni, and at least one nonmagnetic metal selected from a group of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, a rare earth element, Ba, and Sr, and core shell type magnetic particles including an oxide coating layer made to cover surfaces of at least some of the magnetic metal particles and made of oxide containing at least the one nonmagnetic metal as one of constituents of the magnetic metal particles. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a high-frequency core-shell magnetic material, a device apparatus using the same, and an antenna apparatus.

  In recent years, magnetic materials have been applied to device devices such as electromagnetic wave absorbers, magnetic inks, and inductance elements, and their importance is increasing year by year. These parts utilize the characteristics of the magnetic permeability real part (relative magnetic permeability real part) μ ′ or the magnetic permeability imaginary part (relative magnetic permeability imaginary part) μ ″ of the magnetic material according to the purpose. For example, the inductance element uses high μ ′ (and low μ ″), and the electromagnetic wave absorber uses high μ ″. For this reason, when actually used as a device, μ ′ and μ ″ must be controlled in accordance with the frequency band used by the device. In recent years, since the frequency band of equipment used has become higher, there is a strong demand for a technique for manufacturing a material that can control μ ′ and μ ″ at a high frequency.

  As a magnetic material for an inductance element used in a high frequency range of 1 MHz or higher, ferrite or amorphous alloy is mainly used. These magnetic materials have no loss in the range of 1 MHz to 10 MHz (low μ ″), have high μ ′, and exhibit good magnetic properties. However, this magnetic material does not always have satisfactory characteristics because the magnetic permeability μ ′ decreases in a higher frequency range of 10 MHz or higher.

  For this reason, development of inductance elements by thin film technology such as sputtering and plating has been actively conducted, and it has been confirmed that excellent characteristics are exhibited even in a high frequency range. However, thin film technology such as sputtering requires large equipment and requires precise control of film thickness and the like, so that it is not always satisfactory in terms of cost and yield. In addition, the inductance element based on the thin film technology has a problem of lacking long-term thermal stability of magnetic characteristics at high temperature and high humidity.

  In addition, a magnetic material having a high μ ′ and a low μ ″ at a high frequency is expected to be applied to a device device of a high frequency communication device such as an antenna device. Current mobile communication terminals perform most of information propagation by transmitting and receiving radio waves. The frequency band of radio waves currently used is a high frequency region of 100 MHz or more. Therefore, attention is focused on electronic components and substrates useful in this high frequency region. In portable mobile communication and satellite communication, radio waves in the high frequency range of the GHz band are used.

  In order to cope with radio waves in such a high frequency range, it is necessary that energy loss and transmission loss in electronic components be small. For example, in an antenna member indispensable for a mobile communication terminal, a radio wave generated from the antenna causes a transmission loss in the transmission process. This transmission loss is not preferable because it is consumed as heat energy in the electronic component and the substrate and causes heat generation in the electronic component. As a result, since the radio wave to be transmitted to the outside is canceled, it is necessary to transmit a stronger radio wave than necessary, and there is a problem in terms of effective use of power. These problems of transmission loss become more prominent as the antenna member is made smaller.

  In recent years, with increasing demands for smaller and lighter communication equipment, each electronic component has been reduced in size and saved space. It is essential to ensure the distance from the electronic components and the substrate. For this reason, since it is forced to have an unnecessary space, there exists a problem that it is difficult to attain space saving.

  Thus, antennas using dielectric ceramics have been developed, and space saving can be achieved by achieving miniaturization of the antenna. However, since the dielectric has a dielectric loss, the transmission loss increases as a result, transmission / reception sensitivity cannot be obtained, and the use of the dielectric as an auxiliary antenna is limited. In addition, the dielectric tends to narrow the resonance frequency of the antenna, which is not preferable as a broadband antenna.

  As a method of reducing the size and power consumption of antennas, electronic components or electronic components that have a high magnetic permeability (high μ ', low μ' ') are engulfed by the electromagnetic waves that reach the electronic components in the communication device or the substrate from the antenna. There is a method for performing transmission and reception without causing radio waves to reach the substrate. As a result, it is possible to reduce the size and power consumption of the antenna, but at the same time, it is possible to widen the resonance frequency of the antenna, which is more preferable.

  A normal high magnetic permeability member is a metal or an alloy, but since these are metals, the resistance is low and the antenna characteristics are deteriorated, so that they cannot be used. When using a high magnetic permeability member as an antenna substrate, it is also necessary for the high magnetic permeability member to have high insulation.

  On the other hand, when a high-permeability member of an insulating oxide typified by ferrite is used for an antenna substrate, deterioration of antenna characteristics due to low resistance can be suppressed, but at a high frequency of several hundred Hz, it approaches the resonance frequency and transmission loss due to resonance is reduced. It becomes noticeable and cannot be used.

  In addition, when using a high magnetic permeability member as an antenna board | substrate, thickness of 10 micrometers or more as a material thickness is required also as strong as 100 micrometers or more. At present, there is no thick insulating high magnetic permeability member having a high permeability in a high frequency band, particularly in the GHz band, and having a thickness of 10 μm or more, more specifically 100 μm or more. For this reason, as a material for the antenna substrate, there is a demand for an insulating, thick film high permeability member (high μ ′, low μ ″) that can suppress transmission loss as much as possible and can be used even for high-frequency radio waves. .

  On the other hand, the electromagnetic wave absorber uses high μ ″ to absorb noise generated with higher frequency of the electronic device and reduce malfunctions such as malfunction of the electronic device. Examples of the electronic device include a semiconductor element such as an IC chip and various communication devices. Such electronic devices are various such as those used in a high frequency range of 1 MHz to several GHz, and further several tens of GHz or more.

  In particular, in recent years, electronic devices used in a high frequency range of 1 GHz or more tend to increase. Conventionally, an electromagnetic wave absorber of an electronic device used in a high frequency range is manufactured by a binder molding method in which ferrite particles, carbonyl iron particles, FeAlSi flakes, FeCrAl flakes and the like are mixed with a resin. However, these materials have extremely low μ ′ and μ ″ in a high frequency range of 1 GHz or more, and satisfactory characteristics are not necessarily obtained. In addition, a material synthesized by a mechanical alloying method or the like has a problem of low yield due to lack of long-term thermal stability.

Patent Document 1 discloses a core-shell magnetic material in which metal fine particles are coated in multiple layers with an inorganic material as a magnetic material used for high frequency.
JP 2006-97123 A

  The present invention has been made in consideration of the above circumstances, and the object of the present invention is to provide a core-shell magnetic material having excellent characteristics in a high frequency band, particularly in the GHz band, a device device using the same, and an antenna To provide an apparatus.

  The core-shell magnetic material of one embodiment of the present invention includes at least one magnetic metal selected from the group consisting of Fe, Co, and Ni, Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, and a rare earth element. Amorphous magnetic metal particles containing at least one nonmagnetic metal selected from Ba, Sr; and at least a part of the surface of the magnetic metal particles, and one of the components of the magnetic metal particles And a core-shell magnetic particle including an oxide coating layer made of an oxide containing at least one nonmagnetic metal.

  A device apparatus according to an aspect of the present invention includes the core-shell magnetic material according to the aspect described above.

  An antenna device according to one aspect of the present invention includes the core-shell magnetic material according to the above aspect.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the core-shell type magnetic material which has the outstanding characteristic in a high frequency band, especially a GHz band, a device apparatus using this, and an antenna apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
The core-shell magnetic material of the present embodiment includes at least one magnetic metal selected from the group consisting of Fe, Co, Ni, Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, An amorphous magnetic metal particle containing at least one nonmagnetic metal selected from Ba and Sr; and at least a part of the surface of the magnetic metal particle, and is one of the components of the magnetic metal particle Core-shell magnetic particles including an oxide coating layer made of an oxide containing at least one nonmagnetic metal.

  By having the said structure, the core-shell type magnetic material which has the outstanding characteristic in a high frequency band, especially a GHz band is implement | achieved. Specifically, high magnetic permeability (high μ ′, low μ ″) and insulation can be realized in a desired high frequency band, and for example, a magnetic material that suppresses transmission loss suitable for an antenna device is provided. . In addition, a magnetic material having excellent absorption characteristics suitable for a radio wave absorber in a desired high frequency band is provided. Furthermore, a magnetic material excellent in thermal stability of magnetic properties for a long time is provided.

  The magnetic metal contained in the magnetic metal particles contains at least one selected from the group consisting of Fe, Co, and Ni, and is particularly preferable because an Fe-based alloy, a Co-based alloy, and an FeCo-based alloy can achieve high saturation magnetization. The Fe-based alloy contains Ni, Mn, Cu or the like as the second component, and examples thereof include FeNi alloy, FeMn alloy, and FeCu alloy. Examples of the Co-based alloy include Ni, Mn, Cu, and the like as the second component, such as a CoNi alloy, a CoMn alloy, and a CoCu alloy. Examples of the FeCo-based alloy include alloys containing Ni, Mn, Cu and the like as the second component. These second components are effective components for improving the high-frequency magnetic properties of the core-shell magnetic particles.

  Among magnetic metals, it is particularly preferable to use an FeCo-based alloy. The amount of Co in FeCo is preferably 10 atomic% or more and 50 atomic% or less from the viewpoint of satisfying thermal stability and oxidation resistance and a saturation magnetization of 2 Tesla or more. A more preferable amount of Co in FeCo is in the range of 20 atomic% to 40 atomic% from the viewpoint of further increasing saturation magnetization.

  The nonmagnetic metal contained in the magnetic metal particles is at least one metal selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr. These non-magnetic metals are elements that have low standard Gibbs energy of oxide formation and are easily oxidized, and are included as one of the constituent components of the oxide coating layer that coats magnetic metal particles, providing stable insulation. it can. Among these, Al and Si are preferable because they are easily dissolved in Fe, Co, and Ni, which are the main components of the magnetic metal particles, and contribute to the improvement of the thermal stability of the core-shell magnetic particles. In particular, it is preferable to use at least one element selected from Al and Si because thermal stability and oxidation resistance are increased.

  The amount of the nonmagnetic metal is preferably 0.001 atomic% or more and 25 atomic% or less with respect to the magnetic metal from the viewpoint of satisfying high thermal stability, high oxidation resistance, and high saturation magnetization. Among these, it is more preferable to contain 0.001 atomic% or more and 5 atomic% or less, More preferably, it is 0.01 atomic% or more and 5 atomic% or less. In particular, when at least one element selected from Al and Si (when combined) is used, it is preferably contained in an amount of 0.001 atomic% to 5 atomic% with respect to the magnetic metal.

  Magnetic metal particles are amorphous. By being amorphous, the electric resistance of the magnetic metal particles can be increased, and therefore, a decrease in magnetic permeability due to eddy current loss can be suppressed. In addition, there is an advantage that it is excellent in oxidation resistance and corrosion resistance as compared with the crystallized one. Further, being amorphous means that there is no magnetocrystalline anisotropy, and high magnetic permeability can be realized. Furthermore, in the case of an amorphous material, magnetic anisotropy can be easily induced in one direction by a magnetic field, and excellent high-frequency magnetic characteristics can be realized.

  The magnetic metal particles preferably contain at least one additive metal selected from B, Si, C, Ti, Zr, Hf, Nb, Ta, Mo, Cr, Cu, and W, which is different from the nonmagnetic metal. These additive metals are effective metals for making the crystalline phase of the magnetic metal particles amorphous. Among them, B, Nb, Zr, and Hf are particularly effective, and B is the most effective. is there.

  The additive metal is preferably contained in an amount of 0.001 atomic% to 25 atomic% with respect to the entire magnetic metal particle from the viewpoint of satisfying high thermal stability, high oxidation resistance, high saturation magnetization, and high magnetic permeability. In particular, the amount of B when B is used as the additive element is preferably 9 atomic% or more and 25 atomic% or less with respect to the entire magnetic metal particle. When B is less than 9 atomic%, it becomes difficult to make the magnetic metal particles amorphous, and when it is more than 25 atomic%, the ratio of the magnetic phase contained in the magnetic metal particles decreases and the magnetic permeability decreases. It is not preferable.

  It is also effective to replace a part of B as at least one of Nb, Zr, or Hf as the additive metal. Nb, Zr, and Hf are preferable because they have the effect of increasing the crystallization temperature of the magnetic metal phase and can promote the amorphization of the magnetic metal particles. In this case, the additive metal contains at least one of Nb, Zr, or Hf and B, and the total ratio of Nb, Zr, or Hf with respect to the entire magnetic metal particle is 0.5 atom% or more and 7 atoms. %, And the ratio of B with respect to the entire magnetic metal particles is 4 atomic% or more and 20 atomic% or less from the viewpoint of satisfying high thermal stability, high oxidation resistance, and high saturation magnetization. preferable.

  It is preferable that at least two of the magnetic metal, the nonmagnetic metal, and the additive metal contained in the magnetic metal particles are in solid solution with each other. The solid solution can promote the amorphization of the magnetic metal particles and improve the thermal stability and oxidation resistance, thereby improving the high-frequency magnetic characteristics. . In addition, the mechanical properties of the core-shell magnetic particles can be improved. That is, if segregated at the grain boundaries or surfaces of the magnetic metal particles without being dissolved, it may be difficult to effectively improve the mechanical properties.

  Although the magnetic metal particles are amorphous, it does not exclude that they are partially crystallized. It can be judged from the X-ray diffraction pattern and the electron beam diffraction pattern that the magnetic metal particles are amorphous. In the X-ray diffraction pattern, a broad weak peak appears instead of a sharp strong peak as in the case of crystals. In the electron diffraction pattern, halo ring appears instead of a clear spot. The term “amorphous” as used herein refers to a state in which the half-width of the strongest peak of the magnetic phase in X-ray diffraction is 0.4 ° or more, more preferably 3.0 ° or more.

  The composition analysis of magnetic metal particles can be performed, for example, by the following method. For example, non-magnetic metals such as Al and added metals can be analyzed by ICP emission analysis, TEM-EDX, XPS, SIMS, or the like. According to the ICP emission analysis, the magnetic metal particle (core) portion dissolved by weak acid, the residue dissolved by alkali or strong acid (oxide shell), and the analysis result of the whole particle are compared. The composition of the metal particles can be confirmed, that is, the amount of nonmagnetic metal or additive metal in the magnetic metal particles can be measured.

  In addition, according to TEM-EDX, the general composition of magnetic metal particles can be confirmed by squeezing the beam onto magnetic metal particles (core) and shell, irradiating EDX, and semi-quantifying. Furthermore, according to XPS, the bonding state of each element constituting the magnetic metal particle can be examined.

  The magnetic metal particles preferably have an average particle size of 1 nm to 1000 nm, preferably 1 nm to 100 nm, and more preferably 10 nm to 50 nm. If the average particle size is less than 10 nm, superparamagnetism may occur and the amount of magnetic flux may decrease. On the other hand, if the average particle size exceeds 1000 nm, eddy current loss increases in the high frequency region, and the magnetic characteristics in the intended high frequency region may be degraded.

  In the core-shell type magnetic particle, when the particle size of the magnetic metal particle is increased, the magnetic domain structure is more stable in terms of energy than the single-domain structure. At this time, the core-shell magnetic particles having a multi-domain structure have lower permeability high-frequency characteristics than that of the single-domain structure. For this reason, when the core-shell magnetic particles are used as a high-frequency magnetic member, it is preferable that the core-shell magnetic particles exist as magnetic metal particles having a single magnetic domain structure.

  Since the limit particle size of the magnetic metal particles that maintain the single magnetic domain structure is about 50 nm or less, the average particle size of the magnetic metal particles is preferably 50 nm or less. From the above points, it is desirable that the magnetic metal particles have an average particle diameter of 1 nm to 1000 nm, preferably 1 nm to 100 nm, and more preferably 10 nm to 50 nm.

  The magnetic metal particles may be spherical, but are preferably flat or rod-shaped having a large aspect ratio (for example, 10 or more). The rod shape includes a spheroid. Here, “aspect ratio” refers to the ratio of height to diameter (height / diameter). In the case of a spherical shape, the aspect ratio is 1 because the height is also equal to the diameter. The aspect ratio of the flat particles is (diameter / height). The aspect ratio of the bar is (bar length / bar bottom diameter). However, the aspect ratio of the spheroid is (major axis / minor axis).

  When the aspect ratio is increased, magnetic anisotropy depending on the shape can be imparted, and the high frequency characteristics of the magnetic permeability can be improved. In addition, when a desired member is produced by integrating the core-shell magnetic particles, it can be easily oriented by a magnetic field, and the high-frequency characteristics of magnetic permeability can be improved. Further, by increasing the aspect ratio, it is possible to increase the critical particle diameter of magnetic metal particles having a single magnetic domain structure, for example, a particle diameter exceeding 50 nm. In the case of a spherical magnetic metal particle, the critical particle size for forming a single domain structure is about 50 nm. The flat magnetic metal particles having a large aspect ratio can increase the critical particle size, and the high frequency characteristics of the magnetic permeability do not deteriorate.

  In general, particles having a larger particle size are easier to synthesize, and therefore, a larger aspect ratio is advantageous from the viewpoint of production. Furthermore, by increasing the aspect ratio, the core-shell type magnetic particles having magnetic metal particles can be integrated to produce a desired member, so that the filling rate can be increased. The magnetization can be increased, and as a result, the magnetic permeability can be increased.

  The oxide coating layer covering at least a part of the surface of the magnetic metal particles is made of an oxide or a composite oxide containing at least one nonmagnetic metal that is one of the constituent components of the magnetic metal particles. This oxide coating layer not only improves the oxidation resistance of the internal magnetic metal particles, but also integrates the core-shell magnetic particles covered with the oxide coating layer to produce the desired magnetic material. The particles can be electrically separated to increase the electrical resistance of the member.

  By increasing the electrical resistance of the member, it is possible to suppress eddy current loss at high frequencies and improve the high-frequency characteristics of magnetic permeability. For this reason, it is preferable that an oxide coating layer is electrically high resistance, for example, it is preferable to have a resistance value of 1 mΩ · cm or more.

  As described above, at least one nonmagnetic metal selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr is the standard generated Gibbs energy of the oxide. Is an element that is small and easily oxidizable, and can easily form a stable oxide. Such an oxide coating layer made of an oxide or composite oxide containing at least one nonmagnetic metal can improve adhesion and bonding properties to magnetic metal particles, and also improve the thermal stability of magnetic metal particles. it can.

  Among nonmagnetic metals, Al and Si are preferable because they are easily dissolved in Fe, Co, and Ni, which are the main components of magnetic metal particles, and contribute to the improvement of the thermal stability of the core-shell magnetic particles. A complex oxide containing a plurality of types of nonmagnetic metals also includes a solid solution form.

  The oxide coating layer preferably has a thickness of 0.1 nm to 100 nm, more preferably 0.1 nm to 20 nm. When the thickness of the oxide coating layer is less than 0.1 nm, the oxidation resistance becomes insufficient and the core-shell type magnetic particles covered with the oxide coating layer are integrated to produce a desired member. , The eddy current loss is likely to occur, and the high frequency characteristics of the magnetic permeability may be deteriorated.

  On the other hand, when the thickness of the oxide coating layer exceeds 100 nm, the core-shell type magnetic particles covered with the oxide coating layer are integrated to produce a desired member. There is a possibility that the filling rate of the magnetic metal particles contained in the material will be reduced, resulting in a decrease in the saturation magnetization of the member and a decrease in the permeability.

  Examples of the core-shell magnetic material of the present embodiment include powder, bulk (pellet shape, ring shape, rectangular shape, etc.), and a film shape including a sheet.

  The magnetic sheet contains a core-shell magnetic material and a resin. The core-shell magnetic material preferably occupies a volume ratio of 10% to 70% with respect to the entire sheet. If the volume ratio exceeds 70%, the electrical resistance of the sheet decreases, eddy current loss increases, and high-frequency magnetic characteristics may deteriorate. When the volume ratio is less than 10%, the volume fraction of the magnetic metal is lowered, so that the saturation magnetization of the magnetic sheet is lowered, and thus the magnetic permeability may be lowered. Further, it is desirable that the resin or ceramic occupy a volume ratio of 5% or more and 80% or less. If it is less than 5%, the particles cannot be bound to each other and the strength as a sheet may be lowered. If it exceeds 80%, the volume ratio of the magnetic metal particles in the sheet decreases, and the magnetic permeability may decrease.

  Resin is not particularly limited, but polyester resin, polyethylene resin, polystyrene resin, polyvinyl chloride resin, polyvinyl butyral resin, polyurethane resin, cellulose resin, ABS resin, nitrile-butadiene rubber, styrene-butadiene system Rubber, epoxy resin, phenol resin, amide resin, imide resin, or a copolymer thereof is used.

Moreover, you may use inorganic materials, such as an oxide, nitride, and carbide, instead of resin. Specifically, the inorganic material is an oxide containing at least one metal selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr, AlN, Si. ₃ N ₄ , SiC and the like can be mentioned.

  The method for producing the magnetic sheet is not particularly limited. For example, the magnetic sheet can be produced by mixing a core-shell magnetic material, a resin, and a solvent, forming a slurry, coating, and drying. Alternatively, a mixture of a core-shell magnetic material and a resin may be pressed and molded into a sheet shape or a pellet shape. Further, the core-shell type magnetic material may be dispersed in a solvent and deposited by a method such as electrophoresis.

  The magnetic sheet may have a laminated structure. By making a laminated structure, it becomes possible not only to easily increase the film thickness, but also to improve the high-frequency magnetic characteristics by alternately laminating with nonmagnetic insulating layers. That is, a magnetic layer containing a core-shell type magnetic material is formed into a sheet shape having a thickness of 100 μm or less, and the sheet-like magnetic layer has a stacked structure in which nonmagnetic insulating oxide layers having a thickness of 100 μm or less are alternately stacked. As a result, the high-frequency magnetic characteristics are improved. That is, by setting the thickness of the magnetic layer single layer to 100 μm or less, when a high-frequency magnetic field is applied in the in-plane direction, the influence of the demagnetizing field can be reduced, and only the permeability can be increased. In other words, the high frequency characteristics of the magnetic permeability are improved. Although the lamination method is not particularly limited, the magnetic sheets can be laminated by stacking a plurality of magnetic sheets and press-bonding them by a method such as pressing, or by heating and sintering.

  In the core-shell magnetic material described above, at least one magnetic metal selected from the group consisting of Fe, Co, Ni, Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth element, Ba, and Amorphous magnetic metal particles containing at least one nonmagnetic metal selected from Sr have high saturation magnetization, high magnetic permeability, high thermal stability, and high oxidation resistance. In addition, an oxide coating layer made of an oxide containing at least one nonmagnetic metal that is one of the constituent components of magnetic metal particles coated on at least a part of the surface of the magnetic metal particles has high insulation. As a result, by covering the surface of magnetic metal particles having high saturation magnetization and high magnetic permeability with an oxide coating layer having high insulating properties, eddy current loss that causes loss at high frequencies can be suppressed, A core-shell magnetic material with high thermal stability can be obtained.

(Second Embodiment)
The core-shell magnetic material of the present embodiment is present at least in part between the magnetic metal particles, and is selected from Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr. Other than containing at least one nonmagnetic metal and oxide particles in which the nonmagnetic metal / magnetic metal (atomic ratio) in the particles is larger than the nonmagnetic metal / magnetic metal (atomic ratio) in the oxide coating layer Is the same as in the first embodiment. Accordingly, the description overlapping with the first embodiment is omitted.

  The oxide particles present at least in part between the magnetic metal particles are made of an oxide or composite oxide containing at least one nonmagnetic metal. Here, the presence of at least a part between the magnetic metal particles (cores) may be present between the cores by contacting the oxide particles directly between the cores or between the cores by contacting the shell. .

  The oxide particles were covered with the oxide coating layer as well as improving the oxidation resistance and aggregation suppressing power of the magnetic metal particles, that is, the thermal stability of the magnetic metal particles, like the oxide coating layer. When producing a desired member by integrating the core-shell magnetic particles, the magnetic particles can be electrically separated from each other to increase the electrical resistance of the member. By increasing the electrical resistance of the member, it is possible to suppress eddy current loss at high frequencies and improve the high-frequency characteristics of magnetic permeability. For this reason, it is preferable that an oxide particle is electrically high resistance, for example, it is preferable to have a resistance value of 1 mΩ · cm or more.

  The oxide particles contain at least one nonmagnetic metal selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr. As described above, these nonmagnetic metals are elements that have a small standard Gibbs energy of oxide generation and are easily oxidized, and can easily form a stable oxide. The nonmagnetic metal / magnetic metal (atomic ratio) in the oxide particles is larger than the nonmagnetic metal / magnetic metal (atomic ratio) in the oxide coating layer. As described above, since the ratio of the nonmagnetic metal is high, the oxide particles are more thermally stable than the oxide coating layer. For this reason, the presence of such oxide particles in at least a part between the magnetic metal particles can further improve the electrical insulation between the magnetic metal particles, and the thermal conductivity of the magnetic metal particles. Stability can be improved.

  The oxide particles are more preferably oxide particles containing the same kind of nonmagnetic metal contained in the magnetic metal particles, that is, the same kind of nonmagnetic metal as the nonmagnetic metal contained in the oxide coating layer. This is because the oxide particles containing the same kind of non-magnetic metal improve the thermal stability of the magnetic metal particles.

  The oxide particles preferably have an average particle size of 1 nm or more and 100 nm or less, and more preferably the oxide particles have a particle size smaller than that of the magnetic metal particles. When the average particle size is 1 nm or less, the electrical insulation between the magnetic metal particles and the thermal stability of the magnetic metal particles are insufficient, which is not preferable. Further, when the average particle size is 100 nm or more, the ratio of the oxide particles contained in the entire core-shell type magnetic material is increased, that is, the ratio of the magnetic metal particles contained in the entire core-shell type magnetic material is reduced, and the member is saturated. This is not preferable because it may cause a decrease in magnetization and a decrease in magnetic permeability. Similarly, when the particle size of the oxide particles is large, the saturation magnetization of the member may be lowered and the permeability may be lowered. In view of the above, the oxide particles preferably have an average particle size of 1 nm or more and 100 nm or less, and more preferably the oxide particles have a particle size smaller than that of the magnetic metal particles.

  In order to obtain the effect of improving the high-frequency characteristics of the core-shell magnetic material by the oxide particles, it is necessary that a large number of oxide particles exist between the magnetic metal particles in the core-shell magnetic material. The number of oxide particles varies depending on the particle size of the magnetic metal particles and the particle size of the oxide particles, but as a guideline, the number of oxide particles is preferably larger than 10% of the number of core-shell magnetic particles. However, if the number of oxide particles is too large with respect to the number of core-shell magnetic particles, a decrease in saturation magnetization occurs due to a decrease in magnetic metal particles, which leads to a decrease in permeability. As a guide, the number is desirably less than 200% of the number of core-shell magnetic particles. However, the above is only a guideline and slightly differs depending on the particle size of the magnetic metal particles and the particle size of the oxide particles. That is, the particle diameter of the oxide particles is preferably smaller than the particle diameter of the magnetic metal particles as described above, but the ratio of the two particle diameters, that is, (particle diameter of oxide particles) / (magnetic metal particle When the particle size is relatively large, the number of oxide particles may be small. When (particle size of oxide particles) / (particle size of magnetic metal particles) is relatively small, the number of oxide particles is large. Is desirable.

  Note that in this embodiment, in order to realize more excellent characteristics, it is desirable that the composition and thickness of the oxide coating layer and the composition and particle size of the oxide particles be as uniform as possible.

  According to the core-shell magnetic material of the present embodiment, the presence of the oxide particles makes it possible to further improve the high-frequency characteristics of the magnetic permeability and improve the thermal stability.

  In the core-shell magnetic material of the first and second embodiments, the material structure is SEM (Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), and the diffraction pattern (including confirmation of solid solution) is TEM diffraction, XRD (X -Ray Diffraction), the identification and quantitative analysis of the constituent elements are ICP (Inductively coupled plasma) emission analysis, X-ray fluorescence analysis, EPMA (Electron Probe Micro-Analysis), EDX (Energy Dispersive X-ray MS). Secondary Ion Mass Spectrometry Etc., can be respectively discriminated (analysis). The average particle diameter of magnetic metal particles and oxide particles is determined from the average of a large number of particle diameters by averaging the longest diagonal line and the shortest diagonal line of each particle by TEM observation and SEM observation. Is possible. The film thickness of the oxide film coating layer can be obtained by TEM observation.

  The manufacturing method of the core-shell magnetic material of the first and second embodiments is not particularly limited. For example, a step of manufacturing magnetic metal particles that are composite particles of a magnetic metal, a nonmagnetic metal, and an additive metal, a step of coating the surface of the composite particles with carbon, and heat-treating the composite particles coated with carbon in a reducing atmosphere. Manufacture is possible through a step of removing carbon and a step of oxidizing the composite particles to form an oxide coating layer on the surfaces of the magnetic metal particles.

  The process for producing the composite particles is not particularly limited, but it is preferable to use a thermal plasma method or the like. For example, argon (Ar) is introduced into a high frequency induction thermal plasma apparatus as a plasma generating gas to generate plasma, and a powder in which a magnetic metal, a nonmagnetic metal, and an additive metal are dissolved, and Ar is used as a carrier gas. The composite particles are synthesized by spraying.

  The step of coating the surface of the composite particle with carbon is not particularly limited, but in the step of manufacturing the composite particle, a method such as introducing acetylene gas or methane gas into the carrier gas as a carbon coating raw material is preferable. Thereby, particles coated with carbon on magnetic metal particles are obtained.

  The step of heat-treating the carbon-coated composite particles in a reducing atmosphere to carbonize the carbon is not particularly limited. Examples of the reducing atmosphere include hydrogen or nitrogen containing a reducing gas such as carbon monoxide and methane, or It is preferable to perform the heat treatment in an argon atmosphere or in an atmosphere of nitrogen or argon in a state where the periphery of the object to be heated is covered with a carbon material.

  The atmosphere of nitrogen or argon containing a reducing gas is preferably formed by an air flow, and the air flow rate is preferably 10 mL / min or more. Heating in a reducing atmosphere is preferably performed at a temperature of 100 ° C to 800 ° C. If the heating temperature is less than 100 ° C., the reduction reaction may progress slowly. On the other hand, when the temperature exceeds 800 ° C., the agglomeration and grain growth of the deposited metal fine particles may proceed in a short time. The reduction temperature and time are not particularly limited as long as the conditions allow at least the reduction of the carbon coating layer. The reduction time is determined in consideration of the reduction temperature, and is preferably in the range of 10 minutes to 10 hours, for example.

The step of oxidizing the composite particles is not particularly limited as long as it is an oxidizing atmosphere such as oxygen or CO ₂ . In the case of using oxygen, if the oxygen concentration is high, the oxidation proceeds instantaneously and there is a risk of aggregation due to heat generation, etc., so oxygen is preferably 5% or less in the inert gas, more preferably 10 ppm to 3%. The range is desirable, but not particularly limited thereto. The heating temperature is preferably from room temperature to 800 ° C. If it exceeds 800 ° C., the aggregation / growth of magnetic metal particles proceeds in a short time, which may deteriorate the magnetic properties.

  With the manufacturing method as described above, the core-shell magnetic material of the embodiment can be manufactured.

(Third embodiment)
The device apparatus of this embodiment is a high-frequency device apparatus having the core-shell magnetic material of the first or second embodiment. Therefore, the description overlapping with the first or second embodiment is omitted. This device device is, for example, a high-frequency magnetic component such as an inductor, a choke coil, a filter, a transformer, or a radio wave absorber.

  In order to apply to this device apparatus, the core-shell magnetic material allows various processing. For example, in the case of a sintered body, machining such as polishing or cutting is performed, and in the case of powder, mixing with an epoxy resin or a resin such as polybutadiene is performed. Further surface treatment is performed if necessary. When the high-frequency magnetic component is an inductor, choke coil, filter, or transformer, winding processing is performed.

  According to the device apparatus of the present embodiment, a device apparatus having excellent characteristics particularly in the GHz band can be realized.

(Fourth embodiment)
The antenna device of the present embodiment is an antenna device having the core-shell magnetic material of the first or second embodiment. Therefore, the description overlapping with the first or second embodiment is omitted. The antenna device according to the present embodiment includes a power supply terminal, an antenna element to which the power supply terminal is connected at one end, and a core-shell magnetic material for suppressing transmission loss of electromagnetic waves radiated from the antenna element.

  FIG. 1 is a configuration diagram of the antenna device of the present embodiment. 1A is a perspective view, and FIG. 1B is a cross-sectional view taken along arrow AA in FIG. The core-shell magnetic material 2 is provided between the antenna element 6 to which the power supply terminal 4 is connected at one end and the wiring board 8. The wiring board 8 is, for example, a wiring board of a portable device, and is surrounded by, for example, a metal casing.

  For example, when an antenna of a mobile device emits electromagnetic waves, if the antenna and a metal such as a casing of the mobile device are close to each other more than a certain distance, the induction current generated in the metal prevents the electromagnetic waves from being emitted. However, by arranging the core-shell magnetic material in the vicinity of the antenna, even if the antenna and a metal such as a casing are brought close to each other, no induced current is generated, radio wave communication can be stabilized, and the portable device can be downsized.

  When the antenna element 6 radiates electromagnetic waves by inserting the core-shell magnetic material 2 between the two antenna elements 6 sandwiching the feeding terminal 4 and the wiring board 8 as in the present embodiment, The induction current generated in the wiring board 8 can be suppressed, and the radiation efficiency of the antenna device can be increased.

(Fifth embodiment)
In the antenna device of the present embodiment, the antenna device is provided above the finite ground plane, the rectangular conductor plate provided on the finite ground plane, one side connected to the finite ground plane, and a bent portion substantially parallel to the one side. Between the finite ground plane and the antenna, which is disposed substantially parallel to the finite ground plane, extends in a direction substantially perpendicular to the first side, and the feed point is located near the other side of the rectangular conductor plate facing the other side. And a magnetic body provided in at least a part of the space. This magnetic body is the core-shell magnetic material described in the first or second embodiment. Therefore, the description overlapping with the first or second embodiment is omitted.

  Here, “upper” is an expression for indicating a positional relationship based on the case where the finite ground plane is below, and is not necessarily an expression indicating that it is always above the vertical direction. Further, the term “above” includes a case where two elements are in contact with each other.

  FIG. 2 is a configuration diagram of the antenna device of the present embodiment. 2A is a perspective view, FIG. 2B is a sectional view, and FIG. 2C is a sectional view of a modification.

  The antenna device includes a finite ground plane 10, a rectangular conductor plate 12 provided above the finite ground plane 10, an antenna 14 disposed substantially parallel to the finite ground plane 10 above the finite ground plane 10, and the finite ground plane 10 and the antenna 14. And a magnetic body 16 provided in at least a part of the space. In FIG. 2, the magnetic body 16 is inserted between the finite ground plane 10 and the rectangular conductor plate 12. In FIG. 2A, the magnetic body 16 is illustrated separately from the antenna device for easy understanding of the configuration of the antenna device.

  In FIG. 2B, a space is provided between the magnetic body 16, the finite ground plane 10, and the rectangular conductor plate 12. However, in order to enhance the effect of inserting the magnetic body 16, it is more desirable to eliminate these spaces and bring the magnetic body 16 into contact with the finite ground plane 10 and the rectangular conductor plate 12. Further, in FIG. 2B, the magnetic body 16 is inserted only between the rectangular conductor plate 12 and the finite ground plane. However, as in the modification of FIG. The antenna 14 may be inserted into the antenna 14, or may be inserted between the antenna 14 and the rectangular conductor plate 12.

  However, from the viewpoint of adhesion between the magnetic body 16 and the finite ground plane 10, the rectangular conductor plate 12, and the antenna 14, it may be necessary to intervene other materials in the space between them. In such a case, the dielectric occupies the space between the finite ground plane 10 and the antenna 14 other than the space occupied by the magnetic material, and the dielectric and the magnetic material have the same refractive index. It is more preferable to select a combination of magnetic material.

  In the case of a magnetic material alone or a combination of a magnetic material and a dielectric material having different refractive indexes, reflection of radio waves occurs at the interface between the magnetic material and air, or the interface between the magnetic material and the dielectric material. This is because if there is a loss, the radiation efficiency of the antenna device is deteriorated, and if there is no loss, the band is narrowed. By making the refractive index of the space constant, unnecessary radio wave reflection can be suppressed, and deterioration of radiation efficiency can be suppressed.

  Both the finite ground plane 10 and the rectangular conductor plate 12 are made of a conductive material. One side of the rectangular conductor plate 12 is connected to the finite ground plane 10 and is electrically short-circuited. And the bending part 18 substantially parallel to this one side is provided. The antenna 14 is provided above the rectangular conductor plate 12, and the antenna 14 extends in a substantially vertical direction on one side where the rectangular conductor plate 12 is in contact with the finite ground plane 10. The feeding point 22 of the antenna 14 is located in the vicinity of the other side facing the one side of the rectangular conductor plate 12. In FIG. 2, the antenna 14 is a dipole antenna.

  The bent portion 18 of the rectangular conductor plate 12 may be formed by bending a rectangular conductor plate, or if electrically equivalent, two rectangular conductor plates may be prepared instead of being bent. May be physically and electrically connected by a method such as soldering. In the antenna device of FIG. 2, the bent portion 18 of the rectangular conductor plate 12 is a right angle, and is composed of a portion parallel to the finite ground plane 10 and a portion perpendicular to the finite ground plane 10. However, this structure is not essential, and it is not particularly necessary to have this structure as long as electromagnetic wave propagation under the rectangular conductor plate 10 can be obtained. That is, it is not always necessary to bend the rectangular conductor plate 12 at a right angle or to provide a portion parallel or perpendicular to the finite ground plane 10.

  Further, the fact that the feeding point 22 of the antenna 14 is located in the vicinity of the other side facing the one side of the rectangular conductor plate 12 means that the position of the feeding point 22 is 6 minutes from the other side of the electromagnetic wave having the operating frequency of the antenna 14. It means the range of 1 wavelength or less. The reason is that the position adjustment range of the feeding point 22 for antenna matching is within this range as described later.

  FIG. 2 illustrates the case where the antenna 14 is a dipole antenna. The dipole antenna of FIG. 2 arranges two linear conductors in a straight line and feeds power therebetween.

  FIG. 3 is a configuration diagram of a first modification of the antenna device according to the present embodiment. In this modification, a plate-shaped dipole antenna is applied as the antenna 14. The plate-shaped dipole antenna feeds the center where two conductor plates are lined up, and the dipole is processed obliquely so that the distance between the two conductor plates increases as the side closer to the feed point 22 moves away from the feed point One of the antenna variants. The plate-shaped dipole antenna has an advantage that a wider band characteristic can be realized than a dipole antenna using a linear conductor.

  FIG. 4 is a configuration diagram of a second modification of the antenna device according to the present embodiment. 4A is a perspective view, FIG. 4B is a cross-sectional view, and FIG. 4C is a further modification of the second modification. In this modification, a monopole antenna is applied as the antenna 14. The monopole antenna is an antenna in which the linear conductor far from the rectangular conductor plate 12 is eliminated from the dipole antenna shown in FIG. In order to realize further miniaturization of the antenna device, the monopole antenna is preferable to the dipole antenna.

  As shown in FIGS. 2 (a), 2 (b), 3, 4 (a), and (b), the magnetic body 16 is at least partly between the antenna 14 and the rectangular conductor plate 12, for example, rectangular. It is inserted between the conductor plate 12 and the finite ground plane 10.

  With the above configuration, the antenna device according to the present embodiment can achieve impedance matching even when the antenna device is downsized including a low profile, and can obtain wideband characteristics.

  The embodiments of the present invention have been described above with reference to specific examples. The above embodiment is merely given as an example and does not limit the present invention. In the description of the embodiment, the description of the core-shell type magnetic material, the device device using the same, the antenna device, etc., which is not directly necessary for the description of the present invention is omitted. The elements related to the core-shell magnetic material, the device device using the same, the antenna device, and the like can be appropriately selected and used.

  In addition, all core-shell magnetic materials that include elements of the present invention and whose design can be changed as appropriate by those skilled in the art, device devices using the same, and antenna devices are included in the scope of the present invention. The scope of the present invention is defined by the appended claims and equivalents thereof.

  Hereinafter, examples of the present invention will be described in more detail in comparison with comparative examples. In addition, the measurement of the average particle diameter of the magnetic metal particles and oxide particles in the following examples and comparative examples is performed based on TEM observation. Specifically, the average of the longest diagonal line and the shortest diagonal line of each particle projected by TEM observation (photograph) is used as the particle diameter, and the average is obtained. For the photograph, take an average value of three or more unit areas of 10 μm × 10 μm. The thickness of the oxide coating layer is determined by TEM observation. Specifically, three or more photographs are taken by TEM observation in a unit area of 10 μm × 10 μm, and oxide coating layers of individual particles included in the range are obtained, and an average value thereof is obtained. Further, the quantity ratio of the number of particles is calculated by counting the number of core-shell magnetic particles and oxide particles existing in this range.

  The composition analysis of the microstructure is performed based on the EDX analysis. By this analysis, the magnitude relationship between the nonmagnetic metal / magnetic metal (atomic ratio) in the oxide particles and the nonmagnetic metal / magnetic metal (atomic ratio) in the oxide coating layer is determined.

Example 1
Argon is introduced as a plasma generating gas at a rate of 40 L / min into the chamber of the high frequency induction thermal plasma apparatus to generate plasma. The plasma in this chamber contains FeCoAlB solid solution powder having an average particle diameter of 10 μm and Fe: Co: Al: B of 70: 30: 2.5: 25 as an ingredient, and Al powder having an average particle diameter of 3 μm. It is injected at 3 L / min with argon (carrier gas) so as to be 2.5 at% with respect to FeCo 100 in the solid solution powder (that is, the total amount of Al with respect to FeCo is 5 at%, of which 2.5 at% is FeCoAlB The remaining 2.5 at% is added as an Al powder as a solid solution powder).

  Simultaneously with the injection, acetylene gas as a carbon coating material is introduced into the chamber together with a carrier gas to obtain particles in which alloy particles are coated with carbon. The carbon-coated alloy particles were reduced at 600 ° C. under a hydrogen flow of 500 mL / min and a concentration of 99%, cooled to room temperature, then taken out in an oxygen-containing atmosphere and oxidized to obtain a core-shell type magnetic material. To manufacture.

  The obtained core-shell type magnetic material is composed of core-shell type magnetic metal particles and oxide particles. The average particle diameter of the magnetic metal particles contained in the core-shell type magnetic metal particles is 10 nm, and the thickness of the oxide coating layer is 2.1 nm. It is. The magnetic metal particle of the core is composed of Fe—Co—Al—B, and the oxide coating layer is composed of Fe—Co—Al—B—O. In addition, there are a large number of oxide particles composed of Al—O (partially FeCoB solid solution) between the core-shell magnetic particles and between the magnetic metal particles. Al / (Fe + Co) in the oxide particles is larger than Al / (Fe + Co) in the oxide coating layer. The number of oxide particles is about 50% of the number of core-shell magnetic particles.

  Such a core-shell magnetic material and a resin are mixed at a ratio of 100: 10, and the film is thickened to obtain an evaluation material.

(Example 2)
The raw material powder is an FeCoAlNbB solid solution powder having an average particle size of 10 μm and Fe: Co: Al: Nb: B in an atomic ratio of 70: 30: 2.5: 4: 20, compared to FeCo100 in the solid solution powder. Except for using Al powder with an average particle size of 3 μm adjusted to 5 at%, it is the same as Example 1 (that is, the total amount of Al with respect to FeCo is 5 at%, of which 2.5 at% is FeCoAlNbB solid solution powder) The remaining 2.5 at% is charged as Al powder).

  The obtained core-shell magnetic material is composed of core-shell magnetic metal particles and oxide particles. The magnetic metal particles contained in the core-shell magnetic metal particles have an average particle diameter of 11 nm and the oxide coating layer has a thickness of 1.9 nm. It is. The magnetic metal particles of the core are composed of Fe—Co—Al—Nb—B, and the oxide coating layer is composed of Fe—Co—Al—Nb—B—O. In addition, a large number of oxide particles composed of Al—O (partially FeCoNbB solid solution) exist between the core-shell magnetic particles and between the magnetic metal particles. Al / (Fe + Co) in the oxide particles is larger than Al / (Fe + Co) in the oxide coating layer. The number of oxide particles is about 50% of the number of core-shell magnetic particles.

  Such a core-shell magnetic material and a resin are mixed at a ratio of 100: 10, and the film is thickened to obtain an evaluation material.

(Example 3)
The raw material powder is an FeCoAlZrB solid solution powder having an average particle size of 10 μm and an Fe: Co: Al: Zr: B atomic ratio of 70: 30: 2.5: 4: 20, and 2 for FeCo100 in the solid solution powder. Except for using Al powder with an average particle diameter of 3 μm adjusted to 5 at%, the same as in Example 1 (that is, the total amount of Al with respect to FeCo is 5 at%, of which 2.5 at% is FeCoAlZrB solid solution) As the powder, the remaining 2.5 at% is charged as Al powder).

  The obtained core-shell magnetic material is composed of core-shell magnetic metal particles and oxide particles. The average particle diameter of the magnetic metal particles contained in the core-shell magnetic metal particles is 10 nm, and the thickness of the oxide coating layer is 2.0 nm. It is. The magnetic metal particles of the core are composed of Fe—Co—Al—Zr—B, and the oxide coating layer is composed of Fe—Co—Al—Zr—B—O. In addition, there are a large number of oxide particles composed of Al—O (partially FeCoZrB solid solution) between the core-shell magnetic particles and between the magnetic metal particles. Al / (Fe + Co) in the oxide particles is larger than Al / (Fe + Co) in the oxide coating layer. The number of oxide particles is about 50% of the number of core-shell magnetic particles.

  Such a core-shell magnetic material and a resin are mixed at a ratio of 100: 10, and the film is thickened to obtain an evaluation material.

Example 4
The raw material powder has an average particle size of 10 μm and Fe: Co: Al: Hf: B in an atomic ratio of 70: 30: 2.5: 4: 20, and FeCoAlHfB solid solution powder, and 2 for FeCo100 in the solid solution powder. Except for using Al powder with an average particle diameter of 3 μm adjusted to 5 at%, the same as Example 1 (that is, the total Al content with respect to FeCo is 5 at%, of which 2.5 at% is FeCoAlHfB solid solution) As the powder, the remaining 2.5 at% is charged as Al powder).

  The obtained core-shell type magnetic material is composed of core-shell type magnetic metal particles and oxide particles. The average particle size of the magnetic metal particles contained in the core-shell type magnetic metal particles is 12 nm, and the thickness of the oxide coating layer is 2.2 nm. It is. The magnetic metal particle of the core is composed of Fe—Co—Al—Hf—B, and the oxide coating layer is composed of Fe—Co—Al—Hf—B—O. In addition, there are many oxide particles composed of Al—O (partially FeCoHfB solid solution) between the core-shell magnetic particles and between the magnetic metal particles. Al / (Fe + Co) in the oxide particles is larger than Al / (Fe + Co) in the oxide coating layer. The number of oxide particles is about 50% of the number of core-shell magnetic particles.

  Such a core-shell magnetic material and a resin are mixed at a ratio of 100: 10, and the film is thickened to obtain an evaluation material.

(Example 5)
The raw material powder is 0.65 at% with respect to FeCoSiB solid solution powder having an average particle size of 10 μm and Fe: Co: Si: B in an atomic ratio of 70: 30: 1.3: 25, and FeCo100 in the solid solution powder. Except for making the Si powder having an average particle diameter of 3 μm adjusted to the same as Example 1, the total amount of Si with respect to FeCo is 1.3 at%, of which 0.65 at% is FeCoSiB solid solution powder. The remaining 0.65 at% is added as Si powder).

  The obtained core-shell magnetic material is composed of core-shell magnetic metal particles and oxide particles. The average particle diameter of the magnetic metal particles contained in the core-shell magnetic metal particles is 10 nm, and the thickness of the oxide coating layer is 2.1 nm. It is. The core magnetic metal particles are composed of Fe—Co—Si—B, and the oxide coating layer is composed of Fe—Co—Si—B—O. In addition, a large number of oxide particles composed of Si—O (partially FeCoB solid solution) exist between the core-shell magnetic particles and between the magnetic metal particles. Si / (Fe + Co) in the oxide particles is larger than Si / (Fe + Co) in the oxide coating layer. The number of oxide particles is about 50% of the number of core-shell magnetic particles.

  Such a core-shell magnetic material and a resin are mixed at a ratio of 100: 10, and the film is thickened to obtain an evaluation material.

(Example 6)
Example 1 is the same as Example 1 except that the raw material powder is only FeCoAlB solid solution powder having an average particle size of 10 μm and Fe: Co: Al: B of 70: 30: 5: 25 in atomic ratio.

  The obtained core-shell magnetic material is composed of core-shell magnetic metal particles and oxide particles. The average particle diameter of the magnetic metal particles contained in the core-shell magnetic metal particles is 13 nm, and the thickness of the oxide coating layer is 2.5 nm. It is. The magnetic metal particle of the core is composed of Fe—Co—Al—B, and the oxide coating layer is composed of Fe—Co—Al—B—O. Further, there are almost no oxide particles between the core-shell magnetic particles and between the magnetic metal particles. That is, the number of oxide particles is 10% or less of the number of core-shell magnetic particles.

  Such a core-shell magnetic material and a resin are mixed at a ratio of 100: 10, and the film is thickened to obtain an evaluation material.

(Comparative Example 1)
The raw material powder has an average particle size of 10 μm and Fe: Co: Al in an atomic ratio of 70: 30: 2.5, and an average particle adjusted to 2.5 at% with respect to FeCo100 in the solid solution powder. Except for using Al powder with a diameter of 3 μm, the same as Example 1 (that is, the total Al content with respect to FeCo is 5 at%, of which 2.5 at% is FeCoAl solid solution powder and the remaining 2.5 at%. % Is input as Al powder), and is the same as Example 1.

  The obtained core-shell magnetic material is composed of core-shell magnetic metal particles and oxide particles. The average particle diameter of the magnetic metal particles contained in the core-shell magnetic metal particles is 22 nm, and the thickness of the oxide coating layer is 2.7 nm. It is. The core magnetic metal particles are composed of Fe—Co—Al, and the oxide coating layer is composed of Fe—Co—Al—O. In addition, there are a large number of oxide particles composed of Al—O (partially FeCo solid solution) between the core-shell magnetic particles and between the magnetic metal particles. Al / (Fe + Co) in the oxide particles is larger than Al / (Fe + Co) in the oxide coating layer. The number of oxide particles is about 50% of the number of core-shell magnetic particles.

  Such a core-shell magnetic material and a resin are mixed at a ratio of 100: 10, and the film is thickened to obtain an evaluation material.

  Table 1 shows an outline of the magnetic metal particles and the oxide coating layer of the core-shell magnetic particles used in the obtained Examples 1 to 4 and Comparative Example 1.

  Further, with respect to the evaluation materials of Examples 1 to 4 and Comparative Examples 1 and 2, the permeability real part (μ ′), the change with time of the magnetic permeability real part (μ ′) after 100 hours, and Examine electromagnetic wave absorption characteristics. The results are shown in Table 2 below.

1) Permeability real part μ '
Using the PMM-9G1 system made by Lyowa Denshi Co., Ltd., the induced voltage value and the impedance value were measured when air was set as the background and when the sample was placed at 1 GHz, respectively. The magnetic permeability real part μ ′ is derived from the impedance value. A sample processed to a size of 4 × 4 × 0.5 mm is used.

2) Temporal change of permeability real part μ ′ after 100 hours After leaving the sample for evaluation in a high temperature and humidity chamber at 60 ° C. and 90% humidity for 100 hours, the permeability real part μ ′ is measured again. , Change with time (permeability real part μ ′ after being left for 100H / permeability real part μ ′ before being left) is obtained.

3) Electromagnetic wave absorption characteristics A metal thin plate with a thickness of 1 mm and the same area is bonded to the electromagnetic wave irradiation surface of the sample for evaluation and the opposite surface, and in the free space using the S11 mode of the sample network analyzer under the electromagnetic wave of 2 GHz. Measured by the reflected power method. The reflected power method is a method of measuring how much dB the reflection level from a sample is reduced compared to the reflection level of a thin metal plate (complete reflector) to which the sample is not bonded. Based on this measurement, the amount of electromagnetic wave absorption is defined as the amount of return loss, and the relative amount when the amount of absorption in Comparative Example 1 is taken as 1.

  As is apparent from Table 1, in the core-shell magnetic materials according to Examples 1 to 6, at least one element selected from FeCo that is a magnetic metal and Al and Si that are nonmagnetic metals, and an additive metal B or B-Nb , B-Zr, B-Hf, and a magnetic metal particle having an average particle size of about 10 to 13 nm contains at least one element selected from nonmagnetic metal Al and Si, which is one of the components of the magnetic metal particle It turns out that it is comprised with the core-shell type magnetic particle coat | covered with the oxide coating layer of the thickness of 1.9-2.5 nm. It can also be seen that the crystallinity of the magnetic metal particles is amorphous. In contrast, although the magnetic material according to Comparative Example 1 has a core-shell structure, it can be seen that the magnetic metal has a slightly large particle size of 22 nm and is crystalline. In Examples 1 to 5 and Comparative Example 1, a large number of oxide particles are present between the magnetic metal particles, and in Example 6, there are almost no oxide particles between the magnetic metal particles. I understand.

  As can be seen from Table 2, the core-shell magnetic materials according to Examples 1 to 6 have superior magnetic properties as compared with the material of Comparative Example 1. This is because the core-shell magnetic material according to Examples 1 to 6 has an “insulating core-shell structure”, “the magnetic metal has a small particle size due to the additive metal”, and “the magnetic metal particles are amorphous. It is considered that the high quality and high magnetic permeability at high frequency can be realized by “being quality”. In addition, Examples 1 to 5 are particularly superior to Example 6, but this is because the magnetic metal particles are more stable due to the presence of a large number of insulating oxide particles between the magnetic metal particles. Therefore, it is considered that high permeability can be realized. The magnetic permeability real part (μ ′) is only 1 GHz, but shows a flat frequency characteristic, which is almost the same value even at 100 MHz.

  Further, it can be seen that the core-shell magnetic materials of Examples 1 to 6 have very high thermal stability with little change over time in the real permeability (μ ′) after 100 hours. This is because the magnetic metal particles have a homogeneous core-shell structure covered with an oxide coating layer containing a non-magnetic metal, which is one of the constituent components, and the magnetic metal particles are amorphous. This is probably because the metal particles became more stable and high thermal stability was realized. On the other hand, it can be seen that the material according to Comparative Example 1 is slightly inferior in thermal stability as compared with the materials of Examples 1 to 6 because the magnetic metal particles are crystalline. In addition, compared with Example 6, Examples 1 to 5 are particularly excellent in thermal stability. This is because the presence of a large number of insulating oxide particles between the magnetic metal particles causes the magnetic metal It is believed that the particles become more stable and can achieve high thermal stability.

  As described above, the core-shell magnetic material of Example 1 has a high magnetic permeability (μ ′) at 1 GHz and excellent thermal stability. For example, an inductor, a filter, a transformer, a choke coil, a cellular phone, and a wireless LAN in the 1 GHz band. There is a possibility that it can be used as a high magnetic permeability component (using high μ ′ and low μ ″) such as an antenna substrate for equal use. Further, since the electromagnetic wave absorption characteristics at 2 GHz are also excellent, there is a possibility that it can be used as an electromagnetic wave absorber (using high μ ″) in the 2 GHz band. That is, it can be seen that even a single material can be used as a high magnetic permeability component or an electromagnetic wave absorber by changing the operating frequency band, and exhibits a wide range of versatility.

It is a block diagram of the antenna apparatus of 4th Embodiment. It is a block diagram of the antenna apparatus of 5th Embodiment. It is a block diagram of the 1st modification of the antenna device of 5th Embodiment. It is a block diagram of the 2nd modification of the antenna device of 5th Embodiment.

Explanation of symbols

2 Core shell type magnetic material 4 Feed terminal 6 Antenna element 8 Wiring board 10 Finite ground plane 12 Rectangular conductor plate, comb-shaped linear conductor 14 Antenna 16 Magnetic body 16a First magnetic body layer 16b Second magnetic body layer 18 Bending portion 20 Coaxial line 22 Feed point

Claims (13)

At least one magnetic metal selected from the group consisting of Fe, Co, Ni, and at least one nonmagnetic material selected from Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr An amorphous magnetic metal particle containing a metal; and an oxide containing at least one nonmagnetic metal that is coated on at least a part of the surface of the magnetic metal particle and is one of the components of the magnetic metal particle An oxide coating layer comprising:
A core-shell magnetic material comprising core-shell magnetic particles.   The magnetic metal particles include at least one additive metal selected from B, Si, C, Ti, Zr, Hf, Nb, Ta, Mo, Cr, Cu, and W, which is different from the nonmagnetic metal. The core-shell magnetic material according to claim 1.   A particle containing at least one nonmagnetic metal present in at least part of the magnetic metal particles and selected from Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr 2. The oxide particles according to claim 1, wherein the non-magnetic metal / magnetic metal (atomic ratio) in the oxide coating layer includes oxide particles larger than the non-magnetic metal / magnetic metal (atomic ratio) in the oxide coating layer. 2. The core-shell magnetic material according to 2. The magnetic metal particles have an average particle diameter of 1 nm or more and 1000 nm or less;
The oxide coating layer has a thickness of 0.1 nm or more and 100 nm or less;
The core-shell magnetic material according to any one of claims 1 to 3, wherein the oxide particles have an average particle diameter of 1 nm or more and 100 nm or less. The nonmagnetic metal and the additive metal are both contained in an amount of 0.001 atomic% to 25 atomic% with respect to the entire magnetic metal particle,
3. The core-shell magnetic material according to claim 2, wherein at least two of the magnetic metal, the nonmagnetic metal, and the additive metal are in solid solution with each other.   The core-shell magnetic material according to any one of claims 1 to 5, wherein the magnetic metal particles contain FeCo, and Co is contained in FeCo in an amount of 10 atomic percent to 50 atomic percent.   The nonmagnetic metal is at least one element selected from Al and Si, and at least one element selected from Al and Si is contained in an amount of 0.001 atomic% to 5 atomic% with respect to the magnetic metal. The core-shell magnetic material according to any one of claims 1 to 6.   3. The core-shell magnetic material according to claim 2, wherein the additive metal is B, and B is contained in an amount of 9 atomic% to 25 atomic% with respect to the entire magnetic metal particle.   The additive metal includes at least one of Nb, Zr, or Hf and B, and the total ratio of Nb, Zr, or Hf with respect to the entire magnetic metal particle is 0.5 atomic% or more and 7 atomic%. 3. The core-shell magnetic material according to claim 2, wherein the ratio of B is 4 atom% or more and 20 atom% or less with respect to the entire magnetic metal particle.   The core-shell magnetic material according to any one of claims 1 to 9, wherein the magnetic metal particles have an aspect ratio of 10 or more.   A device apparatus comprising the core-shell magnetic material according to any one of claims 1 to 10.   An antenna device comprising the core-shell magnetic material according to any one of claims 1 to 10. With a finite ground plane,
A rectangular conductor plate provided above the finite ground plane, having one side connected to the finite ground plane and having a bent portion substantially parallel to the one side;
An antenna which is disposed substantially parallel to the finite ground plane above the finite ground plane, extends in a direction substantially perpendicular to the one side, and a feeding point is located in the vicinity of the other side facing the one side of the rectangular conductor plate;
A magnetic body provided in at least a part of the space between the finite ground plane and the antenna;
Have
The antenna device according to claim 12, wherein the magnetic body is the core-shell magnetic material.

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