A soft magnetic underlayer with negative uniaxial magnetocrystalline anisotropy for suppression of spike noise and wide adjacent track erasure in perpendicular recording media
A soft magnetic underlayer with negative uniaxial magnetocrystalline anisotropy for suppression of spike noise and wide adjacent track erasure in perpendicular recording media
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DOI：
10.1063/1.2177126
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发表时间：
2006-04-15
影响因子：
3.2
通讯作者：
Takahashi, Migaku
中科院分区：
文献类型：
--
作者：
Hashimoto, Atsushi;Saito, Shin;Takahashi, Migaku
尖峰噪声的抑制和宽邻道擦除（WATE）是垂直记录介质（PRM）发展中的重要技术问题。为了解决这两个问题，本文提出了一种具有负单轴垂直磁各向异性的软磁衬层（SUL）。磁各向异性通过采用具有负单轴磁晶各向异性（K-u（晶粒））的材料来实现。在SUL中，通过在返回轭的边缘下方实现磁通量的宽分布来抑制WATE，同时通过确保在SUL域中形成Neel壁而不是Bloch壁来消除尖峰噪声。选择具有无序hcp结构的CoIr作为负K-u（晶粒）材料，并制备具有不同Ir含量的c面取向CoIr膜用于实验评估。在测试的薄膜中，具有22 at.发现% Ir提供最小K-u（晶粒）值为-6x10（6）ergs/cm（3）。在平行于膜平面施加的场作用下，该膜表现出软磁性质，这归因于c平面片织构的高结晶对称性。使用CoIr SUL制造的PRM被证实显示出比传统结构低得多的尖峰噪声和WATE。(C)2006年，美国物理学会。
The suppression of spike noise and wide adjacent track erasure (WATE) are important technical issues in the development of a perpendicular recording medium (PRM). As a solution to both of these problems, this paper presents a type of soft magnetic underlayer (SUL) with negative uniaxial perpendicular magnetic anisotropy. The magnetic anisotropy is achieved by employing a material with negative uniaxial magnetocrystalline anisotropy (K-u(grain)). WATE is suppressed in the SUL by realizing wide distribution of magnetic flux below the edge of the return yoke, while spike noise is eliminated by ensuring the formation of a Neel wall instead of a Bloch wall in SUL domains. CoIr with the disordered hcp structure is selected as a negative K-u(grain) material, and c-plane-oriented CoIr films with various Ir contents are prepared for experimental evaluation. Among the films tested, the CoIr film with 22 at. % Ir is found to provide the minimum K-u(grain) value of -6x10(6) ergs/cm(3). Under a field applied parallel to the film plane, this film exhibits soft magnetic properties, attributable to the high crystallographic symmetry of the c-plane sheet texture. A PRM fabricated using the CoIr SUL is confirmed to display substantially lower spike noise and WATE compared to conventional structures. (C) 2006 American Institute of Physics.