薄膜磁気ヘッドおよびこれを用いた磁気ディスク装置

Thin film magnetic head and magnetic disk drive using the same

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the decrease of the amount of a magnetic flux inside a magnetic material with respect to a high frequency signal even if the film thickness of a magnetic film in a plane facing a magnetic recording medium is made two times as large as the surface permeation depth s. <P>SOLUTION: In this thin film magnetic head, a first magnetic core 16 and a second magnetic core 12 formed surrounding an electric conductor that generates a magnetic field of a magnetic recording signal are provided, the first magnetic core and the second magnetic core are connected to each other at a part away from a magnetic recording medium and are arranged with a magnetic gap 20 held at a part facing the magnetic recording medium, and a surface facing a magnetic recording medium of the first magnetic core is formed, being smaller than a surface facing a magnetic recording medium of the second magnetic core. In the facing surfaces of the magnetic recording media, width Tw that regulates the track width Tw and film thickness t of the first magnetic core are set so as to satisfy Tw≤2s≤t condition when the skin permeation depth of a magnetic flux with the maximum recording frequency f of a magnetic recording signal as a parameter is defined as s(s =√(2p/ωμ), wherein p is resistivity of the first magnetic core, ω=2πf, and μ is magnetic permeability). The first magnetic core contains Fe alloy having 40 to 60% Ni in weight. <P>COPYRIGHT: (C)2005,JPO&NCIPI
【課題】 磁気記録媒体対向面における磁性膜の膜厚を表皮浸透深さsの2倍以上としても、高周波信号に対する磁性材内部の磁束量が減少するのを抑制する。 【解決手段】 磁気記録信号の磁界を発生する電気導体を取り囲んで形成された第1の磁気コア16と第2の磁気コア12とを有し、第1の磁気コアと第2の磁気コアは磁気記録媒体から離れた部位で互いに接合され、磁気記録媒体に対向する部位で磁気ギャップ20を保って配置され、第1の磁気コアの磁気記録媒体に対向する面が第2の磁気コアの磁気記録媒体に対向する面よりも小さく形成され、磁気記録媒体の対向面において、第1の磁気コアのトラック幅を規制する幅Twと膜厚tが、磁気記録信号の最大記録周波数fをパラメータとする磁束の表皮浸透深さをs{s=√(2ρ/ωμ)、ただし、ρは第1の磁気コアの抵抗率、ω=2πf、μは第1の磁気コアの透磁率}としたときに、Tw≦2s≦tの条件を満たすように設定されてなり、第1の磁気コアは、重量比で40〜60%Niを有するFe合金を含有することを特徴とする。 【選択図】 図1

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