Patent Number: 6,297,929

Title: Magnetic storage apparatus

Abstract: The proposed magnetic storage apparatus has the following features. The frequency at which data is recorded is selected to be 45 MHz. The thickness, resistivity and relative permeability of the magnetic film of which the magnetic poles of the magnetic head used in the apparatus are made are designed considering the eddy current loss. Also, the relation of .mu.d.sup.2 /.rho..ltoreq.500 is satisfied where d (.mu.m) is the thickness of the magnetic film of which the magnetic poles of the magnetic head are made, .rho.(.mu..OMEGA.-cm) is the resistivity, and .mu.is the relative permeability in a low-frequency range. Under these conditions, the amount of attenuation of recording magnetic field is reduced to 10% or below, and problems of writing blur and overwrite value variation which occur as the recording frequency changes can be solved. Moreover, the media data rate is 15 megabytes per sec., and the areal data-recording density is 500 megabits per square inch or more.

Inventors: Takano; Hisashi (Kodaira, JP), Kitada; Masahiro (Hamura, JP), Suzuki; Mikio (Kokubunji, JP)

Assignee: Hitachi, Ltd.

International Classification: G11B 5/127 (20060101); G11B 5/31 (20060101); G11B 5/012 (20060101); G11B 5/09 (20060101); G11B 5/17 (20060101); G11B 5/39 (20060101); G11B 005/127 (); G11B 005/23 ()

Expiration Date: 10/02/2018