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:
Jan. 16, 2001
Filed:
May. 27, 1998
Tsann Lin, Saratoga, CA (US);
Daniele Mauri, San Jose, CA (US);
Joseph Francis Smyth, Los Altos, CA (US);
Ching Hwa Tsang, Sunnyvale, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A fully-pinned, flux-closed spin valve (SV) magnetoresistive sensor having a reference (pinned) layer with magnetization fixed by a first antiferromagnetic (AFM,) layer, and a keeper layer with magnetization fixed by a second antiferromagnetic (AFM,) layer. The magnetization of the keeper layer is saturated and fixed in an antiparallel orientation to the pinned layer magnetization by an exchange interaction with the AFM2 layer. The magnetic moments of the pinned layer and the keeper layer are approximately matched to form a flux-closed magnetic configuration wherein demagnetizing fields in the pinned layer are largely canceled and magnetostatic interaction with the free layer is reduced. Saturation of the keeper layer magnetization by exchange coupling with the AFM,layer eliminates or reduces magnetization canting at the edges of the keeper layer which can result in signal field shunting through the keeper layer. AFM,and AFM,layers may be formed of the same antiferromagnetic material, such as NiO, or alternatively may be formed of different antiferromagnetic materials, such as Ni—Mn and NiO, respectively.