Magnetic thin strip

Abstract

This magnetic thin strip has a homogeneous structure rather than a structure in which a surface is partially oxidized or an amorphous layer having a high B concentration is provided at a prescribed depth from the surface. The magnetic domain structure appearing on the thin strip surface of the magnetic thin strip comprises striped magnetic domains. The orientation of magnetization in the striped magnetic domains is along an orthogonal direction (X direction) orthogonal to a direction (Y direction) in which the striped magnetic domains extend, and the orientations of magnetization of the striped magnetic domains adjacent in the orthogonal direction (X direction) are antiparallel to each other. A cross section of the magnetic thin strip is a single layer.

Description

Magnetic band

[0001] This invention relates to a magnetic thin band capable of achieving low loss.

[0002] Patent Document 1 proposes a magnetic thin band made of a nanocrystalline alloy having a specific composition containing B, as an example of a magnetic thin band capable of achieving low loss, and which has an amorphous layer with a high concentration of B at a predetermined depth from the surface.

[0003] Japanese Patent Publication No. 2010-189761

[0004] The present invention aims to provide a magnetic thin band having a novel structure different from that of Patent Document 1, and capable of achieving low loss.

[0005] The present invention provides a first magnetic thin strip in which the magnetic domain structure appearing on the surface of the thin strip is striped, the direction of magnetization in the striped magnetic domains is along an orthogonal direction perpendicular to the direction in which the striped magnetic domains extend, the directions of magnetization of adjacent striped magnetic domains in the orthogonal direction are antiparallel to each other, and the cross-section is a single layer.

[0006] Furthermore, the present invention provides a second magnetic thin band, which is a first magnetic thin band with a thin band thickness t and a saturation magnetostriction constant λ that satisfy the following conditions. ｓ It has 1.3 × 10 －５ I understand ２ ≤ t ２ / λ ｓ ≤ 2.5 × 10 －４ I understand ２ To provide a magnetic thin band.

[0007] Furthermore, the present invention provides a third magnetic thin band, which is the first or second magnetic thin band, comprising an amorphous phase and a crystalline phase having at least one constituent element and formed within the amorphous phase.

[0008] Furthermore, the present invention provides a fourth magnetic thin band, which is the first or second magnetic thin band, and is made of an Fe-based alloy.

[0009] According to the present invention, the magnetic ribbon has a striped magnetic domain structure that satisfies specific requirements. When a magnetic field is applied in the in-plane direction to a magnetic ribbon having such a magnetic domain structure, a change in magnetization can be caused without domain wall movement. Therefore, the magnetic ribbon of the present invention makes it easier to achieve low loss.

[0010] This figure schematically shows the magnetic domain structure of a magnetic thin band according to an embodiment of the present invention.

[0011] As shown in Figure 1, in the magnetic thin band of the embodiment of the present invention, the magnetic domain structure appearing on the surface of the thin band is striped magnetic domains. In the magnetic thin band of this embodiment, as can be seen from Figure 1, striped magnetic domains can be observed on both the front and back surfaces of the thin band.

[0012] Furthermore, in the magnetic thin band of this embodiment, the direction of magnetization in the striped magnetic domains is along a direction perpendicular to the direction in which the striped magnetic domains extend, and the directions of magnetization of adjacent striped magnetic domains in that perpendicular direction are antiparallel to each other. Specifically, in Figure 1, the direction in which the striped magnetic domains extend is the Y direction, and the perpendicular direction is the X direction. That is, the direction of magnetization in the striped magnetic domains is along the X direction, and the directions of adjacent striped magnetic domains in the X direction are +X and -X directions.

[0013] In addition, the cross-section of the magnetic ribbon of this embodiment is a single layer. In other words, the magnetic ribbon of this embodiment has a homogeneous ribbon structure as a whole. For example, in the magnetic ribbon of this embodiment, surface oxidation hardly occurs, and there is no specific layer at a predetermined depth from the surface. Furthermore, in the magnetic ribbon of this embodiment, crystallization does not occur locally in only specific regions (i.e., partial crystallization does not occur).

[0014] Having such a specific magnetic domain structure allows a magnetization change to occur solely through magnetization rotation without domain wall movement when a magnetic field is applied to the magnetic thin band in the in-plane direction. Therefore, the magnetic thin band of this embodiment can achieve low loss.

[0015] Here, the thickness t of the magnetic strip and the saturation magnetostriction constant λ ｓPreferably, it satisfies the following conditions: 1.3×10 －５ m ２ ≦t ２ / λ ｓ ≦2.5×10 －４ m ２ When appropriate heat treatment is performed while satisfying this condition, the possibility of obtaining the above-described specific magnetic domain structure becomes high. For example, considering the strip thickness t of a general thin strip of about 25 μm, it is understood that the saturation magnetostriction constant λ ｓ is a relatively large value. From this, it is also understood that the reduction in loss due to the above-described specific magnetic domain structure is fundamentally different from the reduction in loss in conventional magnetic thin strips.

[0016] As understood from the above-described principle of loss reduction, it is important that the magnetic thin strip of the present invention has a specific magnetic domain structure. Therefore, the present invention is not limited to a specific composition. For example, the magnetic thin strip may have an amorphous phase composed of an arbitrary and single composition, or may have a homogeneous structure in which a part thereof is microcrystallized and dispersed in the amorphous phase. However, from the viewpoint of easily realizing an appropriate compressive stress for constituting the above-described specific magnetic domain structure, the latter is preferable. That is, it is preferable that the magnetic thin strip includes an amorphous phase and a crystal phase having at least one constituent element and formed in the amorphous phase.

[0017] As an inexpensive and industrially realistic example, the magnetic thin strip is preferably made of an Fe-based alloy. Since the Fe-based alloy is a material having a relatively large magnetostriction and a high magnetization material, it is suitable as the material of the magnetic thin strip of the present embodiment. In particular, the magnetic thin strip may be a nanocrystalline alloy thin strip having an amorphous layer and a plurality of Fe-based crystal phases formed in the amorphous layer. The Fe-based crystal phase may be, for example, an α-Fe crystal phase, or may be an FeSi crystal phase, an FeAl crystal phase, or an FeSiAl crystal phase.

[0018] Hereinafter, embodiments of the present invention will be described in more detail with reference to a plurality of examples.

[0019] (Examples 1-6 and Comparative Examples 1-2) The raw materials were weighed to match the compositions of Examples 1-6 and Comparative Examples 1-2 of the present invention listed in Table 1 below, and then arc-melted. Subsequently, the molten alloys having each respective composition were processed in air using a single-roll liquid quenching method to produce amorphous alloy strips. The roll diameter was 450 mm, the discharge speed from the nozzle was 20 m / s, and the gas blown during peeling from the roll was nitrogen. The produced strips were approximately 60 mm wide and several hundred m long, and had various strip thicknesses t. Furthermore, the amorphous alloy strips of Examples 1-6 and Comparative Examples 1-2 were heat-treated using an infrared lamp furnace (QHC-P616) manufactured by Advance Engineering Co., Ltd., under an Ar atmosphere and under the conditions described in Table 2. After that, all strips were immediately cooled to below the Curie temperature of 295°C within 10 minutes after the holding period was completed. The phase of the magnetic strips after heat treatment was identified by X-ray diffraction. An X-ray diffractometer, a Rigaku Miniflex 600, was used, and the target metal was Cu. The surface of each magnetic threshold was observed using a magneto-optical effect microscope modified from a polarizing microscope, and the magnetic domain structure was identified. The core loss of each magnetic threshold was measured using a B-H analyzer (SY-8219) manufactured by Iwasaki Communication Equipment Co., Ltd. The saturation magnetostriction constant λ of each magnetic threshold was determined. ｓ The measurements were taken using a strain gauge type magnetostrictive measuring instrument manufactured by Toei Kagaku Sangyo Co., Ltd., and the values ​​from each thin strip thickness t to t ２ / λ ｓ The value was calculated. The measurement results are shown in Table 1.

[0020]

[0021]

[0022] In the magnetic domain structure shown in Table 1, the "striped domains" represent the specific magnetic domain structure described above. In contrast, the "striped domains (Note)" in Comparative Example 2 show a structure different from the specific magnetic domain structure described above. Specifically, the magnetic domain structure observed on the surface of the thin band resembles striped domains, but unlike the specific magnetic domain structure, the direction of magnetization in the striped domains is along the direction in which the striped domains extend, and the directions of magnetization of adjacent striped domains in the direction perpendicular to that are antiparallel to each other. To explain this in comparison with the specific magnetic domain structure in Figure 1, in the magnetic thin band of Comparative Example 2, the direction of magnetization in the striped domains is along the Y direction, and the directions of adjacent striped domains in the X direction are +Y and -Y directions.

[0023] As can be seen from Table 1, when the specific magnetic domain structure described above is present, the core loss is 110 or less, whereas in Comparative Examples 1 and 2, which have magnetic domain structures different from the specific magnetic domain structure, the core loss exceeds 110.

[0024] Furthermore, referring to Examples 1 to 6 and Comparative Examples 1 and 2, the thickness t of the magnetic strip and the saturation magnetostriction constant λ ｓ It can be understood that the specific magnetic domain structure described above is easily obtained when the following conditions are met and appropriate heat treatment is performed: 1.3 × 10 －５ I understand ２ ≤ t ２ / λ ｓ ≤ 2.5 × 10 －４ I understand ２

[0025] Although the best embodiment of the present invention has been described, it will be obvious to those skilled in the art that the embodiment can be modified without departing from the spirit of the invention, and such embodiments fall within the scope of the present invention.

[0026] 1. Magnetic thin band

Claims

1. A magnetic thin strip having a stripe-like magnetic domain structure on its surface, wherein the direction of magnetization in the stripe-like magnetic domains is along a direction perpendicular to the direction in which the stripe-like magnetic domains extend, the directions of magnetization of adjacent stripe-like magnetic domains in the perpendicular direction are antiparallel to each other, and the cross-section is a single layer.

2. A magnetic thin band according to claim 1, wherein the thin band thickness t and saturation magnetostriction constant λ satisfy the following conditions. ｓ It has 1.3 × 10 －５ I understand ２ ≤ t ２ / λ ｓ ≤ 2.5 × 10 －４ I understand ２ Magnetic tape.

3. A magnetic thin strip according to claim 1 or claim 2, comprising an amorphous phase and a crystalline phase having at least one constituent element and formed within the amorphous phase.

4. A magnetic thin strip according to claim 1 or claim 2, wherein the magnetic thin strip is made of an Fe-based alloy.

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