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:
Nov. 24, 1998
Filed:
Jul. 16, 1997
William Joseph Gallagher, Ardsley, NY (US);
Stuart Stephen Parkin, San Jose, CA (US);
John Casimir Slonczewski, Katonah, NY (US);
Jonathan Zanhong Sun, Mohegan Lake, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A magnetic tunnel junction (MTJ) device is usable as a magnetic field sensor or as a memory cell in a magnetic random access (MRAM) array. The MTJ device has a 'pinned' ferromagnetic layer whose magnetization is oriented in the plane of the layer but is fixed so as to not be able to rotate in the presence of an applied magnetic field in the range of interest, a 'free' ferromagnetic layer whose magnetization is able to be rotated in the plane of the layer relative to the fixed magnetization of the pinned ferromagnetic layer, and an insulating tunnel barrier layer located between and in contact with both ferromagnetic layers. The pinned ferromagnetic layer is formed as a sandwich of two antiferromagnetically coupled ferromagnetic layers separated by a metallic layer. The free and pinned ferromagnetic layers are located in separate spaced-apart planes so as to not overlap the tunnel barrier layer. An insulating layer surrounds the lateral perimeter of at least the free ferromagnetic layer and supports an electrical lead that makes contact with the free ferromagnetic layer.