JPH05326262A - Magnetic multilayer film - Google Patents
Magnetic multilayer filmInfo
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- JPH05326262A JPH05326262A JP4226487A JP22648792A JPH05326262A JP H05326262 A JPH05326262 A JP H05326262A JP 4226487 A JP4226487 A JP 4226487A JP 22648792 A JP22648792 A JP 22648792A JP H05326262 A JPH05326262 A JP H05326262A
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- Japan
- Prior art keywords
- magnetic
- thickness
- multilayer film
- resonance frequency
- ferromagnetic resonance
- Prior art date
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、高周波磁気デバイス用
磁性多層膜に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic multilayer film for high frequency magnetic devices.
【０００２】[0002]
【従来の技術】コイル，トランス等高周波磁気デバイス
のコア材料としては、できるだけ高い周波数まで大きな
比透磁率が維持され、かつ損失の小さい磁性材料が要求
される。比透磁率μｒはμｒ′を実部、μｒ″を虚部と
して、 μｒ＝μｒ′−ｊ・μｒ″ （１） と表される。ここで（−１）1/2 ＝ｊである。μｒ′は
実効的な比透磁率、μｒ″は損失にそれぞれ対応するた
め、コア材料としては、高周波までμｒ′が高く、μ
ｒ″が低いことが要求される。磁性体に高周波磁場が印
加されると、磁性体内に電流が流れ、磁性体の磁化変化
に制動を与え、損失が生じる。これを渦電流損失とい
う。渦電流損失は磁性体の厚さが（２）式で表される表
皮深さδより厚くなると顕著となる。 δ＝｛２ρｍ／（２πｆ・μｒ′・μ0 ）｝1/2 （２） ここで、ρｍは磁性体の抵抗率、ｆは周波数、μ0 は真
空の透磁率である。フェライト系磁性体はρｍが高いた
めδが厚くなり、１００ＭＨｚ以下の周波数領域では渦
電流損失が問題とならない。このような理由により、従
来、高周波磁気デバイス用コアの主要材料としてはフェ
ライト系磁性体が使用されてきた。図７に従来の代表的
な高周波用磁性材料であるＮｉ−Ｚｎフェライト，フェ
ロクスプレナフェライトにおける比透磁率の周波数特性
を示す。横軸は周波数、縦軸は比透磁率を示す。Ｎｉ−
Ｚｎフェライトでは静的比透磁率μｒ′（０）は３５、
強磁性共鳴周波数は３００ＭＨｚであり、１００ＭＨｚ
付近からμｒ′が低下、μｒ″が増加し始める。一方、
フェロクスプレナフェライトでは、μｒ′（０）は３
５、強磁性共鳴周波数は７００ＭＨｚであり、４００Ｍ
Ｈｚ付近からμｒ′が低下およびμｒ″の増加が始まる
（参考文献：電子材料シリーズ「フェライト」平賀，奥
谷，尾島共著、１９８６，丸善）。近年、磁気デバイス
の小型・高周波化の要請に伴い、１００ＭＨｚ以上の高
周波帯域において使用可能な磁性材料が要求されてい
る。上記のように、従来材料であるフェライト系磁性体
は、μｒ′（０）があまり大きくなく、また百ＭＨｚか
ら数百ＭＨｚでμｒ′の低下、μｒ″の急増が生じるた
め、１００ＭＨｚ以上では使用できない。このため、動
作周波数１００ＭＨｚ以上の小型・高周波磁気デバイス
の実現が困難となっている。2. Description of the Related Art As a core material of a high frequency magnetic device such as a coil or a transformer, a magnetic material which maintains a large relative permeability up to a frequency as high as possible and has a small loss is required. The relative permeability μr is expressed as μr = μr′−j · μr ″ (1) where μr ′ is the real part and μr ″ is the imaginary part. Here, (−1) 1/2 = j. Since μr ′ corresponds to effective relative permeability and μr ″ corresponds to loss, μr ′ is high up to high frequencies as the core material.
r ”is required to be low. When a high-frequency magnetic field is applied to a magnetic material, a current flows in the magnetic material, damping changes in the magnetization of the magnetic material, resulting in loss. This is called eddy current loss. The current loss becomes remarkable when the thickness of the magnetic body becomes thicker than the skin depth δ expressed by the equation (2): δ = {2ρm / (2πf · μr ′ · μ 0 )} 1/2 (2) where Where ρm is the resistivity of the magnetic material, f is the frequency, and μ 0 is the magnetic permeability of the vacuum .. Since ferrite magnetic material has a high ρm, δ becomes thick, and eddy current loss becomes a problem in the frequency region of 100 MHz or less. For this reason, a ferrite-based magnetic material has been used as a main material for a high-frequency magnetic device core in the past. Of relative permeability in cuprena ferrite Shows the wave number characteristics. The horizontal axis is frequency and the vertical axis represents the relative magnetic permeability .Ni-
Zn ferrite has a static relative magnetic permeability μr ′ (0) of 35,
Ferromagnetic resonance frequency is 300MHz, 100MHz
From around, μr ′ decreases and μr ″ starts to increase.
In ferroxplaner ferrite, μr '(0) is 3
5, the ferromagnetic resonance frequency is 700MHz, 400M
Μr ′ starts to decrease and μr ″ starts to increase near Hz (Reference: Electronic Material Series “Ferrite” written by Hiraga, Okutani, Ojima, 1986, Maruzen). In recent years, along with the demand for miniaturization and higher frequency of magnetic devices, there has been a demand for magnetic materials that can be used in a high frequency band of 100 MHz or higher. As described above, the ferrite-based magnetic material that is a conventional material does not have a large μr ′ (0), and decreases from μr ′ from 100 MHz to several hundreds of MHz and causes a rapid increase in μr ″. Therefore, it is difficult to realize a small-sized high-frequency magnetic device having an operating frequency of 100 MHz or more.
【０００３】[0003]
【発明が解決しようとする課題】本発明は上記の欠点を
改善するために提案されたもので、その目的は、従来の
高周波用磁性材料において数百ＭＨｚの周波数帯域で比
透磁率が低く、損失が大きいという点を解決した、高比
透磁率，低損失性を示す磁性多層膜を提供することにあ
る。DISCLOSURE OF THE INVENTION The present invention has been proposed in order to improve the above-mentioned drawbacks, and its purpose is to provide a conventional high frequency magnetic material having a low relative magnetic permeability in a frequency band of several hundred MHz. An object of the present invention is to provide a magnetic multilayer film having high relative permeability and low loss, which solves the problem of large loss.
【０００４】[0004]
【課題を解決するための手段】上記の課題を解決するた
め、本発明は基板上に、シート状磁性体と、同じくシー
ト状非磁性絶縁体とを交互に積層してなる磁性多層膜に
おいて、強磁性共鳴周波数以下の周波数で用いる場合、
前記磁性体の厚さが強磁性共鳴周波数における表皮深さ
以下であり、かつ前記非磁性絶縁体の厚さが前記磁性体
間の電気的絶縁を保ち得る厚さ以上であることを最も主
要な特徴とする。従来の材料とは、材料構成および構造
が異なる。In order to solve the above-mentioned problems, the present invention provides a magnetic multilayer film in which a sheet-shaped magnetic material and a sheet-shaped non-magnetic insulator are alternately laminated on a substrate. When used at frequencies below the ferromagnetic resonance frequency,
Most importantly, the thickness of the magnetic substance is not more than the skin depth at the ferromagnetic resonance frequency, and the thickness of the non-magnetic insulator is not less than the thickness capable of maintaining the electrical insulation between the magnetic substances. Characterize. The material composition and structure are different from conventional materials.
【０００５】[0005]
【作用】本発明によれば、磁性体の厚さを強磁性共鳴周
波数における表皮深さ以下にすることによって、強磁性
共鳴周波数以下の周波数帯域において渦電流損失を抑制
することができる。According to the present invention, the eddy current loss can be suppressed in the frequency band below the ferromagnetic resonance frequency by making the thickness of the magnetic material below the skin depth at the ferromagnetic resonance frequency.
【０００６】[0006]
【実施例】次に本発明の実施例について説明する。図１
は、本発明の磁性多層膜の実施例を示す図であって、基
板４上に磁性体１と非磁性絶縁体２とが交互に積層した
磁性多層膜３が形成されている。磁性体の強磁性共鳴周
波数ｆｋは、図１に示す座標系において、磁化方向をｚ
方向とすると、 ｆｋ＝（γ／２π）｛Ｈｅｚ＋（Ｎｙ−Ｎｚ）４πＭｓ＋Ｈａｚ−Ｈａｙ） ・（Ｈｅｚ＋（Ｎｘ−Ｎｚ）４πＭｓ＋Ｈａｚ−Ｈａｘ）｝1/2 （３） で表される。ここで、γはジャイロ磁気定数、Ｈｅｚは
ｚ方向の外部磁場、Ｎｘ，Ｎｙ，Ｎｚは各々ｘ，ｙ，ｚ
方向の反磁場定数、４πＭｓは磁性体の飽和磁束密度、
Ｈａｘ，Ｈａｙ，Ｈａｚは各々ｘ，ｙ，ｚ方向の異方性
磁場である。ただし、磁性体が図１のように薄膜形状を
なす場合、Ｎｘ＝１となる。今、磁性多層膜を強磁性共
鳴周波数ｆｋ以下の周波数で使用する場合、強磁性共鳴
周波数ｆｋにおける表皮深さは、（２）式により｛２ρ
ｍ／（２πｆｋ・μｒ′・μ0 ）｝1/2 となる。磁性体
の厚さをこの表皮深さ以下にすることによって、ｆｋ以
下では渦電流損失を回避することが可能となる。図１で
は、磁性体１の厚さはこの表皮深さ以下に設定されてい
る。また、非磁性絶縁体２の厚さが薄く、磁性体間の電
気的絶縁が不完全であると、磁性体間に電流が流れてし
まい、渦電流損失が生ずる。図１では非磁性絶縁体の厚
さは、磁性体間の電気的絶縁を保ち得る厚さ以上に設定
されている。EXAMPLES Next, examples of the present invention will be described. Figure 1
FIG. 4 is a diagram showing an embodiment of a magnetic multilayer film of the present invention, in which a magnetic multilayer film 3 in which magnetic substances 1 and nonmagnetic insulators 2 are alternately laminated is formed on a substrate 4. The ferromagnetic resonance frequency fk of the magnetic substance is z in the magnetization direction in the coordinate system shown in FIG.
The direction is expressed by fk = (γ / 2π) {Hez + (Ny−Nz) 4πMs + Haz−Hay) · (Hez + (Nx−Nz) 4πMs + Haz−Hax)} 1/2 (3). Here, γ is a gyro magnetic constant, Hez is an external magnetic field in the z direction, and Nx, Ny, and Nz are x, y, and z, respectively.
Direction demagnetization constant, 4πMs is the saturation magnetic flux density of the magnetic material,
Hax, Hay, and Haz are anisotropic magnetic fields in the x, y, and z directions, respectively. However, when the magnetic body has a thin film shape as shown in FIG. 1, Nx = 1. Now, when the magnetic multilayer film is used at a frequency equal to or lower than the ferromagnetic resonance frequency fk, the skin depth at the ferromagnetic resonance frequency fk is calculated by the formula (2) as {2ρ
m / (2πfk · μr ′ · μ 0 )} 1/2 . By setting the thickness of the magnetic body to be less than this skin depth, it becomes possible to avoid eddy current loss at fk or less. In FIG. 1, the thickness of the magnetic body 1 is set to be equal to or less than the skin depth. If the non-magnetic insulator 2 is thin and the electrical insulation between the magnetic bodies is incomplete, a current will flow between the magnetic bodies, resulting in eddy current loss. In FIG. 1, the thickness of the non-magnetic insulator is set to be equal to or larger than the thickness that can maintain the electrical insulation between the magnetic substances.
【０００７】ここで、磁性体間の電気的絶縁をとれる非
磁性絶縁体の厚さについての検討結果例を示す。図２に
磁性体の厚さを固定し、磁性体間の厚さを変化させた磁
性多層膜における比透磁率（μｒ′，μｒ″）の周波数
特性を示す。磁性体としては５０ｎｍ厚のＮｉＦｅ合金
を、非磁性絶縁体としてはＳｉＯ2 を、基板にはコーニ
ングガラスを使用した。μｒ′，μｒ″はμｒ′（０）
で規格化した。ＳｉＯ2 厚５ｎｍでは、１０ＭＨｚ付近
からμｒ′は低下し始め、μｒ″も明確なピークを示さ
ない振舞いが観察される。このことから、ＳｉＯ2 厚５
ｎｍでは電気的絶縁が不十分であることがわかる。一
方、ＳｉＯ2 厚５０ｎｍでは、ＮｉＦｅ合金の強磁性共
鳴周波数である６５０ＭＨｚ付近にμｒ″のピークが現
れ、６５０ＭＨｚまでμｒ′の低下が生じない振舞いが
観察された。ＳｉＯ2 厚１００ｎｍでは、この傾向は一
層明確となる。このことは、ＳｉＯ2 厚５０ｎｍおよび
ＳｉＯ2 厚１００ｎｍでは、磁性体間の電気的絶縁がほ
ぼ保たれていることを示唆している。以上の検討から、
ＳｉＯ2 厚を５０ｎｍと設定することにより、磁性体間
の電気的絶縁をとることが可能であることがわかる。Here, an example of the result of examination on the thickness of the non-magnetic insulator capable of electrically insulating the magnetic substances will be shown. 2 shows the frequency characteristics of relative permeability (μr ′, μr ″) in a magnetic multilayer film in which the thickness of the magnetic material is fixed and the thickness between the magnetic materials is changed. An alloy, SiO 2 was used as the non-magnetic insulator, and Corning glass was used as the substrate. Μr ′, μr ″ are μr ′ (0)
Standardized in. In SiO 2 thickness 5 nm, .mu.r 'from around 10MHz begins to decrease, .mu.r "even behavior do not show a clear peak is observed. Therefore, SiO 2 thickness 5
It can be seen that the electrical insulation is insufficient in nm. On the other hand, at a SiO 2 thickness of 50 nm, a peak of μr ″ appeared near 650 MHz, which is the ferromagnetic resonance frequency of the NiFe alloy, and a behavior in which μr ′ did not decrease up to 650 MHz was observed. At a SiO 2 thickness of 100 nm, this tendency was observed. This is clearer, which suggests that the electrical insulation between the magnetic substances is almost maintained at the SiO 2 thickness of 50 nm and the SiO 2 thickness of 100 nm.
It can be seen that by setting the SiO 2 thickness to 50 nm, it is possible to electrically insulate the magnetic bodies.
【０００８】高周波磁気デバイス用コアに用いる磁性材
料としては、できるだけ高周波までμｒ′の低下、μ
ｒ″の増加が起きない特性を持つことが要求される。μ
ｒ′の低下、μｒ″の増加は強磁性共鳴周波数ｆｋ付近
から起き始めるため、高周波特性を良くするためには、
強磁性共鳴周波数ｆｋを大きくすることが必要である。
強磁性共鳴周波数ｆｋを大きくするためには、（３）式
よりわかるように磁性体に大きな一軸磁気異方性を持た
せることが有効である。磁性体に一軸磁気異方性を持た
せる方法としては、ｚ方向を容易軸とする大きな磁場
誘導磁気異方性を持たせる、ｚ方向を容易軸とする大
きな歪磁気異方性を持たせる、ｙ方向に大きな反磁場
定数を持たせる、ｚ方向に大きな外部磁場を加える、
などの方法が挙げられる。以下に各々について説明す
る。As the magnetic material used for the core for high frequency magnetic devices, μr ′ is lowered to μ as high as possible,
It is required to have a characteristic that does not cause an increase in r ″.
Since the decrease of r ′ and the increase of μr ″ begin to occur near the ferromagnetic resonance frequency fk, in order to improve the high frequency characteristics,
It is necessary to increase the ferromagnetic resonance frequency fk.
In order to increase the ferromagnetic resonance frequency fk, it is effective to give the magnetic material a large uniaxial magnetic anisotropy, as can be seen from the equation (3). As a method for giving a magnetic substance uniaxial magnetic anisotropy, a large magnetic field induced magnetic anisotropy having the easy axis in the z direction, a large strain magnetic anisotropy having the easy direction in the z direction, give a large diamagnetic field constant in the y direction, add a large external magnetic field in the z direction,
And the like. Each will be described below.
【０００９】まず、のｚ方向を容易軸とする磁場誘導
磁気異方性を持たせるためには、磁性多層膜表面に平行
に直流磁場を印加させて磁場中成膜する方法と、成膜後
磁性多層膜表面に平行に直流磁場を印加させ磁場中熱処
理する方法が挙げられる。磁場誘導磁気異方性による異
方性磁場をＨｉｎとすると、（３）式においてＨｅｚ＝
Ｎｙ＝Ｎｚ＝Ｈａｘ＝Ｈａｙ＝０，Ｎｘ＝１，Ｈａｚ＝
Ｈｉｎとして、強磁性共鳴周波数ｆｋは、 ｆｋ＝（γ／２π）｛Ｈｉｎ（４πＭｓ＋Ｈｉｎ）｝1/2 （４） となる。図３に磁性体としてＣｏＺｒＮｂアモルファス
合金を、非磁性絶縁体としてＳｉＯ2 を、基板としてコ
ーニングガラスを使用した場合の、強磁性共鳴周波数ｆ
ｋのＨｉｎ依存性を示す。強磁性共鳴周波数ｆｋは
（４）式に従い、Ｈｉｎの増加にともない増加する。強
磁性共鳴周波数ｆｋを大きくするためには、Ｈｉｎを大
きくすることが有効である。図４にＨｉｎ＝２０Ｏｅに
おけるＣｏＺｒＮｂ／ＳｉＯ2 多層膜の比透磁率の周波
数特性を示す。強磁性共鳴周波数ｆｋは１．４ＧＨｚで
あり、ＣｏＺｒＮｂ合金のρｍは１２０μΩｃｍ，μ
ｒ′は６００であるため、この時（２）式から表皮深さ
は０．６μｍとなる。図５に、１．４ＧＨｚにおけるＣ
ｏＺｒＮｂ合金厚（ｔｍ）と比透磁率（μｒ′，μ
ｒ″）との関係を示す。厚さ０．６μｍ以下ではμｒ′
の低下は見られないが、０．６μｍ以上ではμｒ′は急
減、μｒ″は急増し始める。このことからＣｏＺｒＮｂ
合金厚を０．６μｍ以下に設定すれば、１．４ＧＨｚ以
下で渦電流損失を抑えられることがわかる。図３ではマ
ージンをもたせ、ＣｏＺｒＮｂ合金厚を１．４ＧＨｚに
おける表皮深さ０．６μｍ以下の０．２μｍ（２００ｎ
ｍ）に、ＳｉＯ2 の厚さを電気的絶縁を保ち得る厚さ
０．０５μｍ（５０ｎｍ）以上である０．１μｍ（１０
０ｎｍ）に設定してある。図４では、μｒ′は１ＧＨｚ
までほぼフラットな特性を示し、強磁性共鳴周波数１．
４ＧＨｚ付近で急減する。一方、μｒ″は１．４ＧＨｚ
付近にピークを持つ特性を示す。ＣｏＺｒＮｂ／ＳｉＯ
2 多層膜のμｒ′（０）は４００程度の値となる。この
特性を図７の従来材料であるＮｉ−Ｚｎフェライトの特
性と比較すると、μｒ′（０）値および強磁性共鳴周波
数ｆｋが各々一桁以上大きな値となり、従来材料と比較
し、比透磁率が高く、損失が小さい特性が得られている
ことがわかる。First, in order to provide the magnetic field-induced magnetic anisotropy with the z direction as the easy axis, a method of applying a DC magnetic field in parallel to the surface of the magnetic multilayer film to form a film in the magnetic field, and a method after the film formation A method of applying a direct-current magnetic field in parallel to the surface of the magnetic multilayer film and performing heat treatment in the magnetic field can be mentioned. Assuming that the anisotropic magnetic field due to the magnetic field-induced magnetic anisotropy is Hin, in the equation (3), Hez =
Ny = Nz = Hax = Hay = 0, Nx = 1, Haz =
As Hin, the ferromagnetic resonance frequency fk is fk = (γ / 2π) {Hin (4πMs + Hin)} 1/2 (4) FIG. 3 shows the ferromagnetic resonance frequency f when CoZrNb amorphous alloy is used as the magnetic substance, SiO 2 is used as the non-magnetic insulator, and Corning glass is used as the substrate.
The dependency of k on Hin is shown. The ferromagnetic resonance frequency fk increases with the increase of Hin according to the equation (4). It is effective to increase Hin in order to increase the ferromagnetic resonance frequency fk. FIG. 4 shows the frequency characteristics of the relative permeability of the CoZrNb / SiO 2 multilayer film at Hin = 20 Oe. The ferromagnetic resonance frequency fk is 1.4 GHz, and ρm of CoZrNb alloy is 120 μΩcm, μ
Since r ′ is 600, the skin depth is 0.6 μm from the equation (2) at this time. Fig. 5 shows C at 1.4 GHz
oZrNb alloy thickness (tm) and relative permeability (μr ', μ
r ″), and μr ′ when the thickness is 0.6 μm or less.
However, when 0.6 μm or more, μr ′ suddenly decreases and μr ″ begins to rapidly increase. From this, CoZrNb
It can be seen that eddy current loss can be suppressed at 1.4 GHz or less by setting the alloy thickness to 0.6 μm or less. In FIG. 3, with a margin, the CoZrNb alloy thickness is 0.2 μm (200 n
m), the thickness of SiO 2 is 0.1 μm (10 μm) which is 0.05 μm (50 nm) or more so that the electrical insulation can be maintained.
0 nm). In FIG. 4, μr ′ is 1 GHz
Shows almost flat characteristics up to ferromagnetic resonance frequency 1.
A sharp decrease near 4 GHz. On the other hand, μr ″ is 1.4 GHz
Shows a characteristic with a peak in the vicinity. CoZrNb / SiO
The μr ′ (0) of the two- layered film has a value of about 400. When this characteristic is compared with the characteristic of the Ni—Zn ferrite which is the conventional material of FIG. 7, the μr ′ (0) value and the ferromagnetic resonance frequency fk each have a value larger by one digit or more, and the relative permeability is higher than that of the conventional material. It can be seen that the characteristics are high and the loss is small.
【００１０】次に、の歪磁気異方性による異方性磁場
Ｈｓｔは磁性体の磁歪定数をλｓ、膜応力をσｆとし
て、 Ｈｓｔ＝４π・２｛（３／２）σｆ・λｓ｝／４πＭｓ （５） と表され、（３）式においてＨｅｚ＝Ｎｙ＝Ｎｚ＝Ｈａ
ｘ＝Ｈａｙ＝０，Ｎｘ＝１，Ｈａｚ＝Ｈｓｔとして、強
磁性共鳴周波数ｆｋは、 ｆｋ＝（γ／２π）｛Ｈｓｔ（４πＭｓ＋Ｈｓｔ）｝1/2 （６） となる。強磁性共鳴周波数ｆｋはＨｓｔの増加にともな
い増加するため、強磁性共鳴周波数ｆｋを大きくするに
はＨｓｔを大きくすることが有効である。磁性体のλｓ
は、例えばＣｏＹでは＋５×１０-6，ＣｏＨｆでは＋３
×１０-6，ＣｏＺｒでは＋３×１０-6，ＣｏＴｉでは＋
１．５×１０-6，ＣｏＴａでは−０．５×１０-6，Ｃｏ
Ｎｂでは−１．５×１０-6，ＣｏＮｂＦｅでは＋８×１
０-6，ＣｏＮｂＮｉでは−７×１０-6，ＣｏＮｂＭｎで
は−３×１０-6である。一般にλｓ，σｆは膜面内で等
方的であるため、Ｈｓｔを発生させるためには、σｆに
異方性を持たせる必要がある。σｆに異方性を持たせる
方法としては、図６に示すように磁性多層膜の形状をス
トライプ状とする方法、および外部から機械的に一方向
に力を加える方法が挙げられる。例えば、図６では、σ
ｆが圧縮性の場合（＜０）、λｓが正ならばｙ方向が、
λｓが負ならばｚ方向が容易軸となるようなＨｓｔが発
生することになる。σｆが引っ張り性の場合（＞０）は
この逆となる。今、σｆ＝１０9 ｄｙｎ／ｃｍ2 ，λｓ
＝＋１０-5とすると、約４０ＯｅのＨｓｔがｙ方向に発
生し、この時４πＭｓ＝１ Teslaとすると、ｆｋ＝１．
９ＧＨｚとなる。Next, the anisotropic magnetic field Hst due to the strain magnetic anisotropy is Hst = 4π · 2 {(3/2) σf · λs} / 4πMs, where λs is the magnetostriction constant of the magnetic material and σf is the film stress. It is expressed as (5), and Hez = Ny = Nz = Ha in the expression (3).
When x = Hay = 0, Nx = 1, and Haz = Hst, the ferromagnetic resonance frequency fk is fk = (γ / 2π) {Hst (4πMs + Hst)} 1/2 (6). Since the ferromagnetic resonance frequency fk increases with an increase in Hst, it is effective to increase Hst in order to increase the ferromagnetic resonance frequency fk. Λs of magnetic material
Is + 5 × 10 −6 for CoY and +3 for CoHf, for example.
× 10 -6, CoZr the + 3 × 10 -6, the CoTi +
1.5 × 10 −6 , CoTa is −0.5 × 10 −6 , Co
-1.5 × 10 −6 for Nb, + 8 × 1 for CoNbFe
0 -6, -7 × 10 -6 In CoNbNi, it is -3 × 10 -6 in CoNbMn. In general, λs and σf are isotropic in the film plane, so that σf needs to have anisotropy in order to generate Hst. As a method of giving anisotropy to σf, there are a method of forming the magnetic multilayer film in a stripe shape as shown in FIG. 6 and a method of mechanically applying a force in one direction from the outside. For example, in FIG.
If f is compressible (<0), then if y is positive, the y direction is
If λs is negative, Hst occurs such that the easy axis is in the z direction. When σf is tensile (> 0), the opposite is true. Now, σf = 10 9 dyn / cm 2 , λs
= + 10 −5 , Hst of about 40 Oe is generated in the y direction. At this time, if 4πMs = 1 Tesla, fk = 1.
It becomes 9 GHz.
【００１１】次に、のｙ方向に大きな反磁場定数を持
たせる方法としては、図６に示すように、磁性多層膜形
状をｙ方向を短辺とするストライプ状とする方法が挙げ
られる。反磁場Ｈｄは、 Ｈｄ＝Ｎｙ・４πＭｓ （７） で表され、（３）式においてＨｅｚ＝Ｎｚ＝Ｈａｘ＝Ｈ
ａｙ＝Ｈａｚ＝０，Ｎｘ＝１として、強磁性共鳴周波数
ｆｋは、 ｆｋ＝（γ／２π）（Ｈｄ・４πＭｓ）1/2 （８） となる。強磁性共鳴周波数ｆｋはＨｄ従ってＮｙの増加
にともなって増加するため、強磁性共鳴周波数ｆｋを大
きくするにはＮｙを大きくすることが有効である。Ｎｙ
は図４の磁性多層膜形状に依存し、長辺と短辺との比が
大きくなるほどＮｙは大きくなる。As a method of providing a large demagnetizing field constant in the y direction, there is a method of forming the magnetic multilayer film into a stripe shape with the short side in the y direction as shown in FIG. The demagnetizing field Hd is represented by Hd = Ny · 4πMs (7), and in the formula (3), Hez = Nz = Hax = H
When ay = Haz = 0 and Nx = 1, the ferromagnetic resonance frequency fk is fk = (γ / 2π) (Hd · 4πMs) 1/2 (8). Since the ferromagnetic resonance frequency fk increases with Hd and accordingly Ny, it is effective to increase Ny in order to increase the ferromagnetic resonance frequency fk. Ny
Depends on the shape of the magnetic multilayer film of FIG. 4, and Ny increases as the ratio of the long side to the short side increases.
【００１２】最後に、の外部磁場（Ｈｅｘｔ）を加え
る方法としては、磁性多層膜を近接させた永久磁石から
の磁場を用いる方法、および磁性多層膜に近接させた導
線に電流を流し発生した磁場を用いる方法が挙げられ
る。（３）式においてＮｙ＝Ｎｚ＝Ｈａｘ＝Ｈａｙ＝Ｈ
ａｚ＝０，Ｎｘ＝１，Ｈｅｚ＝Ｈｅｘｔとして、強磁性
共鳴周波数ｆｋは、 ｆｋ＝（γ／２π）｛Ｈｅｘｔ（Ｈｅｘｔ＋４πＭｓ）｝1/2 （９） となる。強磁性共鳴周波数ｆｋはＨｅｘｔの増加にとも
ない増加するため、強磁性共鳴周波数ｆｋを大きくする
にはＨｅｘｔを大きくすることが有効である。以上、磁
性体厚さを強磁性共鳴周波数における表皮深さ以下に
し、非磁性絶縁体厚さを電気的絶縁を保ち得る厚さ以上
に設定した磁性多層膜において、からの方法によっ
て磁性体に大きな一軸磁気異方性を持たせることによ
り、従来材料に比較し、高周波まで大きな比透磁率を維
持し、低損失な磁性材料を得ることができる。Finally, as a method for applying the external magnetic field (Hext), a method using a magnetic field from a permanent magnet in which the magnetic multi-layer film is in close proximity, and a magnetic field generated by passing an electric current through a conducting wire in close proximity to the magnetic multi-layer film The method of using is mentioned. In the equation (3), Ny = Nz = Hax = Hay = H
When az = 0, Nx = 1, and Hez = Hext, the ferromagnetic resonance frequency fk is fk = (γ / 2π) {Hext (Hext + 4πMs)} 1/2 (9). Since the ferromagnetic resonance frequency fk increases with the increase of Hext, increasing Hext is effective for increasing the ferromagnetic resonance frequency fk. As described above, in the magnetic multilayer film in which the thickness of the magnetic body is set to be equal to or less than the skin depth at the ferromagnetic resonance frequency, and the thickness of the non-magnetic insulator is set to be equal to or more than the thickness capable of maintaining electrical insulation, By providing the uniaxial magnetic anisotropy, it is possible to obtain a magnetic material that maintains a large relative permeability up to a high frequency and has a low loss as compared with a conventional material.
【００１３】なお、磁性体に一軸磁気異方性を持たせる
ためには、上記からのうち複数の方法を併用しても
同様の効果を得ることができる。また、磁性体として
は、ＣｏにＺｒ，Ｎｂ，Ｙ，Ｈｆ，Ｔｉ，Ｍｏ，Ｗ，Ｔ
ａ，Ｓｉ，Ｂ，Ｒｅ，Ｆｅ，Ｎｉのうち単独あるいは複
数の元素を添加したものを、一方、非磁性絶縁体として
は、ＳｉＯ2 ，ＡｌＮ， Ａｌ2 Ｏ3 ，ＢＮ，ＴｉＮ，
ＳｉＣを各々使用しても上記と同様の効果を得ることが
できる。以上、本発明による磁性多層膜では、従来材料
に比べ、高周波まで、高比透磁率，低損失性を示すとい
う改善があった。In order to give the magnetic material uniaxial magnetic anisotropy, the same effect can be obtained even if a plurality of the above methods are used together. Further, as the magnetic substance, Co is added to Zr, Nb, Y, Hf, Ti, Mo, W, T.
One of a, Si, B, Re, Fe and Ni to which a single element or a plurality of elements are added is used as a non-magnetic insulator, while SiO 2 , AlN, Al 2 O 3 , BN, TiN,
Even if each of SiC is used, the same effect as described above can be obtained. As described above, the magnetic multilayer film according to the present invention has an improvement in that it has a high relative permeability and a low loss property even at high frequencies, as compared with the conventional material.
【００１４】[0014]
【発明の効果】以上説明したように、本発明による磁性
多層膜は、数百ＭＨｚの高周波帯域において、比透磁率
が高く、損失が小さいという利点がある。従って、本磁
性多層膜は、動作周波数１００ＭＨｚ以上の小型・高周
波磁気デバイスのコア材料として有用である。As described above, the magnetic multilayer film according to the present invention has the advantages of high relative permeability and small loss in the high frequency band of several hundred MHz. Therefore, the present magnetic multilayer film is useful as a core material for a small-sized and high-frequency magnetic device having an operating frequency of 100 MHz or more.
【図１】本発明の実施例を示す図である。FIG. 1 is a diagram showing an embodiment of the present invention.
【図２】非磁性絶縁体としてのＳｉＯ2 厚を変化させた
場合の比透磁率の周波数特性を示す図である。FIG. 2 is a diagram showing frequency characteristics of relative permeability when the thickness of SiO 2 as a non-magnetic insulator is changed.
【図３】強磁性共鳴周波数の磁場誘導異方性磁場依存性
を示す図である。FIG. 3 is a diagram showing the dependence of a ferromagnetic resonance frequency on a magnetic field-induced anisotropic magnetic field.
【図４】比透磁率の周波数特性を示す図である。FIG. 4 is a diagram showing a frequency characteristic of relative permeability.
【図５】ＣｏＺｒＮｂ合金厚と比透磁率との関係を示す
図である。FIG. 5 is a diagram showing a relationship between CoZrNb alloy thickness and relative permeability.
【図６】本発明の実施例を示す図である。FIG. 6 is a diagram showing an example of the present invention.
【図７】従来の磁性材料における比透磁率の周波数特性
を示す図である。FIG. 7 is a diagram showing frequency characteristics of relative permeability in a conventional magnetic material.
１ 磁性体 ２ 非磁性絶縁体 ３ 磁性多層膜 ４ 基板 1 magnetic material 2 non-magnetic insulator 3 magnetic multilayer film 4 substrate
Claims (5)
ト状非磁性絶縁体とを交互に積層してなる磁性多層膜に
おいて、この磁性多層膜を強磁性共鳴周波数以下の周波
数で使用する場合、前記磁性体の厚さが強磁性共鳴周波
数における表皮深さ以下であり、かつ前記非磁性絶縁体
の厚さが前記磁性体間の電気的絶縁を保ち得る厚さ以上
であることを特徴とする磁性多層膜。1. A magnetic multilayer film comprising sheet-like magnetic bodies and sheet-like non-magnetic insulators alternately laminated on a substrate, when the magnetic multilayer film is used at a frequency lower than a ferromagnetic resonance frequency. The thickness of the magnetic body is less than or equal to the skin depth at the ferromagnetic resonance frequency, and the thickness of the non-magnetic insulator is greater than or equal to the thickness capable of maintaining electrical insulation between the magnetic bodies. A magnetic multilayer film.
を、非磁性絶縁体としてＳｉＯ2 を使用することを特徴
とする請求項１記載の磁性多層膜。2. The magnetic multilayer film according to claim 1, wherein a Co-based amorphous alloy is used as the magnetic substance and SiO 2 is used as the non-magnetic insulator.
μｍ以下とし、ＳｉＯ2 の厚さを５０ｎｍ以上とするこ
とを特徴とする請求項１記載の磁性多層膜。3. A Co-based amorphous alloy having a thickness of 0.6
The magnetic multilayer film according to claim 1, wherein the thickness is not more than μm and the thickness of SiO 2 is not less than 50 nm.
特徴とする請求項１記載の磁性多層膜。4. The magnetic multilayer film according to claim 1, wherein the magnetic material has uniaxial magnetic anisotropy.
ジャイロ磁気定数をγ、異方性磁場をＨｋとするとき、
強磁性共鳴周波数ｆｋ＝（γ／２π）（４πＭｓ・Ｈ
ｋ）1/2 以下の周波数で使用する場合、ρｍ，μｒを磁
性体の抵抗率，比透磁率、μ0 を真空の透磁率とすると
き、磁性体の表皮深さδの最小値は｛２ρｍ／（２πｆ
ｋ・μｒ・μ0 ）｝1/2 であり、前記磁性体の厚さが前
記表皮深さの最小値以下であり、かつ前記非磁性絶縁体
の厚さが前記磁性体間の電気的絶縁を保ち得る厚さ以上
であることを特徴とする請求項１記載の磁性多層膜。5. The saturation magnetic flux density of the magnetic material is 4πMs,
When the gyro magnetic constant is γ and the anisotropic magnetic field is Hk,
Ferromagnetic resonance frequency fk = (γ / 2π) (4πMs · H
k) When used at a frequency of 1/2 or less, when ρm and μr are the resistivity and relative permeability of the magnetic substance and μ 0 is the magnetic permeability of vacuum, the minimum value of the skin depth δ of the magnetic substance is { 2ρm / (2πf
k · μr · μ 0 )} 1/2 , the thickness of the magnetic body is less than or equal to the minimum value of the skin depth, and the thickness of the non-magnetic insulator is electrical insulation between the magnetic bodies. The magnetic multilayer film according to claim 1, wherein the magnetic multilayer film has a thickness equal to or more than the above value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4226487A JP2744945B2 (en) | 1992-03-16 | 1992-08-03 | Magnetic multilayer film |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9020992 | 1992-03-16 | ||
| JP4-90209 | 1992-03-16 | ||
| JP4226487A JP2744945B2 (en) | 1992-03-16 | 1992-08-03 | Magnetic multilayer film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05326262A true JPH05326262A (en) | 1993-12-10 |
| JP2744945B2 JP2744945B2 (en) | 1998-04-28 |
Family
ID=13992099
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07249516A (en) * | 1994-03-11 | 1995-09-26 | Amorphous Denshi Device Kenkyusho:Kk | Magnetic core for micro magnetic element |
| JP2007507873A (en) * | 2003-10-07 | 2007-03-29 | コミツサリア タ レネルジー アトミーク | Method for producing multilayer composite |
| JP2009105368A (en) * | 2007-10-19 | 2009-05-14 | Taida Electronic Ind Co Ltd | Inductor and core thereof |
| DE102014212393A1 (en) * | 2014-06-27 | 2015-12-31 | Continental Teves Ag & Co. Ohg | Method for producing a magnetic core with multiple layers |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4978877A (en) * | 1972-12-11 | 1974-07-30 | ||
| JPS59202614A (en) * | 1983-05-04 | 1984-11-16 | Showa Denko Kk | Magnetic element |
-
1992
- 1992-08-03 JP JP4226487A patent/JP2744945B2/en not_active Expired - Lifetime
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4978877A (en) * | 1972-12-11 | 1974-07-30 | ||
| JPS59202614A (en) * | 1983-05-04 | 1984-11-16 | Showa Denko Kk | Magnetic element |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07249516A (en) * | 1994-03-11 | 1995-09-26 | Amorphous Denshi Device Kenkyusho:Kk | Magnetic core for micro magnetic element |
| JP2007507873A (en) * | 2003-10-07 | 2007-03-29 | コミツサリア タ レネルジー アトミーク | Method for producing multilayer composite |
| JP2009105368A (en) * | 2007-10-19 | 2009-05-14 | Taida Electronic Ind Co Ltd | Inductor and core thereof |
| DE102014212393A1 (en) * | 2014-06-27 | 2015-12-31 | Continental Teves Ag & Co. Ohg | Method for producing a magnetic core with multiple layers |
| CN105321700A (en) * | 2014-06-27 | 2016-02-10 | 大陆-特韦斯贸易合伙股份公司及两合公司 | Method for manufacturing multi-layer magnetic core |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2744945B2 (en) | 1998-04-28 |
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