The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 05, 1998
Filed:
Mar. 19, 1997
Masahiro Tobise, Saitama-ken, JP;
Chiharu Mitsumata, Tochigi-ken, JP;
Hisayuki Miura, Tochigi-ken, JP;
Tetsurou Kawai, Saitama-ken, JP;
Simon Liao, Santa Barbara, CA (US);
Hitachi Metals Ltd., Tokyo, JP;
Applied Magnetics Corporation, Goleta, CA (US);
Abstract
An SAL-type magnetoresistive playback head that is highly sensitive and that limits Barkhausen noise is provided by optimizing the magnetic properties of the permanent magnet film. On top of a lower insulating layer are stacked a soft magnetic bias film (SAL film), a magnetic separating film (shunt film), a magnetoresistive film (MR film), and an upper insulating layer, in that order. The outer sides of the track of the MR film are in direct contact with the permanent magnet film or in indirect contact via a base film. Alternatively, the present invention relates to a spin-valve magnetoresistive playback head. On top of a lower insulating layer are stacked an anti-ferromagnetic film, a fixed magnetizing film, a magnetic separating film, a movable magnetizing film (MR film), and an upper insulating layer, in that order. The outer sides of the track of the movable magnetizing film are in direct contact with the permanent magnet film or in indirect contact via a base film. In either type of playback head, Barkhausen noise is eliminated by using a CoCrPt alloy film having a composition that provides the magnetic properties needed for a permanent magnet film that can handle narrow tracks and narrow gaps, and by specifying a ratio between the thicknesses of the MR film and the permanent magnet film.