CN-121999810-A - Magnetic recording medium, method for manufacturing magnetic recording medium, and magnetic storage device

Abstract

The present invention provides a magnetic recording medium which stably maintains the state that a granular magnetic layer forms a granular structure inside and improves the surface recording density. The magnetic recording medium comprises a substrate, a underlayer, a1 st magnetic layer and a 2 nd magnetic layer in this order, wherein the 1 st magnetic layer contains magnetic particles having an L1 0 structure, the 2 nd magnetic layer comprises magnetic particles having an L1 0 structure, the (111) plane of the magnetic particles contained in the 1 st magnetic layer is covered with any one of VN, si 3 N 4 , YN or TiN at the interface with the 2 nd magnetic layer, the magnetic particles contained in the 2 nd magnetic layer epitaxially grow from the (001) plane of the magnetic particles contained in the 1 st magnetic layer, and the magnetic particles contained in the 1 st magnetic layer and the magnetic particles contained in the 2 nd magnetic layer are columnar crystals penetrating through the 1 st magnetic layer and the 2 nd magnetic layer.

Inventors

• FUKUSHIMA TAKAYUKI
• TIAN DAOSHENG

Assignees

• 株式会社力森诺科硬盘

Dates

Publication Date

20260508

Application Date

20251030

Priority Date

20241101

Claims (4)

1. 1. A magnetic recording medium having, in order, a substrate, an underlayer, a1 st magnetic layer, and a2 nd magnetic layer, The 1 st magnetic layer comprises magnetic particles having a structure of L1 0 , The 2 nd magnetic layer has magnetic particles having an L1 0 structure and a granular structure having a grain boundary portion including hexagonal boron nitride, The (111) plane of the magnetic particles contained in the 1 st magnetic layer is covered with any one of VN, si 3 N 4 , YN or TiN alloy at the interface with the 2 nd magnetic layer, The magnetic particles contained in the 2 nd magnetic layer are epitaxially grown from the (001) plane of the magnetic particles contained in the 1 st magnetic layer, The magnetic particles contained in the 1 st magnetic layer and the magnetic particles contained in the 2 nd magnetic layer are columnar crystals penetrating through the 1 st magnetic layer and the 2 nd magnetic layer respectively.
2. 2. A magnetic recording medium according to claim 1, The magnetic particles with the L1 0 structure contained in the 1 st magnetic layer and the 2 nd magnetic layer are FePt alloy particles.
3. 3. A method for manufacturing a magnetic recording medium having a substrate, a base layer, a1 st magnetic layer, and a2 nd magnetic layer in this order, The 1 st magnetic layer comprises magnetic particles having a structure of L1 0 , The 2 nd magnetic layer has magnetic particles having an L1 0 structure and a granular structure having a grain boundary portion including hexagonal boron nitride, The (111) plane of the magnetic particles contained in the 1 st magnetic layer is covered with any one of VN, si 3 N 4 , YN or TiN alloy at the interface with the 2 nd magnetic layer, The magnetic particles contained in the 2 nd magnetic layer are epitaxially grown from the (001) plane of the magnetic particles contained in the 1 st magnetic layer, The magnetic particles contained in the 1 st magnetic layer and the magnetic particles contained in the 2 nd magnetic layer are columnar crystals penetrating through the 1 st magnetic layer and the 2 nd magnetic layer respectively, The manufacturing method includes a step of forming a layer of any one of TiN alloys of VN, si 3 N 4 , YN by sputtering between a step of forming the 1 st magnetic layer by sputtering and a step of forming the 2 nd magnetic layer by sputtering.
4. 4. A magnetic storage device having the magnetic recording medium of claim 1 or 2.

Description

Magnetic recording medium, method for manufacturing magnetic recording medium, and magnetic storage device Technical Field The present disclosure relates to a magnetic recording medium, a method of manufacturing the magnetic recording medium, and a magnetic storage device. Background In recent years, a thermal-assisted recording method or a microwave-assisted recording method that irradiates a magnetic recording medium with near-field light or microwaves to locally heat the magnetic recording medium, thereby reducing the coercivity and recording the magnetic recording medium has been attracting attention as a next-generation recording method that can achieve a high areal recording density of about 2Tbit/inch 2. When such a magnetic head of the auxiliary recording system is used, a magnetic recording medium having a coercivity of several tens of kOe at room temperature can be recorded easily. As the magnetic particles contained in the magnetic layer of the magnetic recording medium, for example, magnetic particles having a high crystalline magnetic anisotropy constant (Ku) are used. Magnetic particles having a high crystalline magnetic anisotropy constant (Ku) can be miniaturized while maintaining thermal stability, and the coercivity at room temperature can be improved. As magnetic particles having a high crystalline magnetic anisotropy constant (Ku), for example, magnetic particles having a L1 0 structure such as fe—pt alloy particles (Ku: max 7×10 6J/m3) and co—pt alloy particles (Ku: max 5×10 6J/m3) are known. As a magnetic layer using magnetic particles having an L1 0 structure, for example, non-patent document 1 discloses a magnetic layer having a granular structure in which the periphery of FePt magnetic particles having an L1 0 structure is covered with a layer of hexagonal boron nitride. Prior art literature Non-patent literature Non-patent literature 1：B. S. D. Ch. S. Varaprasad et al., "FePt-BN granular HAMR media with high grain aspect ratio and high L1 ordering on corning LotusTM NXT glass", AIP Advances, Volume 13, Issue 3, 035002(2023) Here, it is desired to further increase the surface recording density of the magnetic recording medium. In order to further increase the areal recording density of the magnetic recording medium, it is important to further increase the anisotropy of the magnetic particles while further reducing the particle diameter of the magnetic particles contained in the magnetic layer. As such a magnetic layer, there are proposed FePt magnetic particles oriented in the (001) direction in the L1 0 structure and a magnetic layer having a granular structure including hexagonal boron nitride in the grain boundary portion (hereinafter, simply referred to as "FePt-hBN granular magnetic layer"). Hexagonal boron nitride is a layered structure in which (001) planes are accumulated in parallel, but grain boundary portions are easily formed between FePt magnetic particles, whereby the particle size of the FePt magnetic particles can be reduced. In addition, hexagonal boron nitride has low reactivity with FePt magnetic particles, and therefore standardization of the magnetic particles is not impaired. Further, such hexagonal boron nitride is preferably formed such that its (001) face surrounds the side face of the FePt magnetic particle. However, in the conventional FePt-hBN granular magnetic layer, the magnetic particles and the grain boundary portions are likely to be layered and separated from each other, and a granular structure is not generated in many cases. In addition, the components in the grain boundary portion such as BN are not sufficiently crystallized, and often in an amorphous state. Therefore, even if a magnetic layer having a granular structure (also referred to as a granular magnetic layer) is used, there is a problem that the improvement of the surface recording density of the magnetic recording medium is not achieved in some cases. Disclosure of Invention An object of one embodiment of the present disclosure is to provide a magnetic recording medium in which a granular magnetic layer is stably maintained in a state in which the granular structure is formed inside, and further the areal recording density is improved. Means for solving the problems The above object can be achieved as follows. (1) A magnetic recording medium having, in order, a substrate, an underlayer, a1 st magnetic layer, and a2 nd magnetic layer, The 1 st magnetic layer contains magnetic particles having a structure of L1 0, The 2 nd magnetic layer has a granular structure having a magnetic particle having an L1 0 structure and a grain boundary portion including hexagonal boron nitride, The (111) plane of the magnetic particles contained in the 1 st magnetic layer is covered with any one of VN, si 3N4, YN and TiN alloy at the interface with the 2 nd magnetic layer, The magnetic particles contained in the 2 nd magnetic layer are epitaxially grown from the (001) plane of the magnetic particles contain