Three-state dual spin valve structure

Abstract

A dual spin valve is built with exchange bias on the top and bottom pinned layers and a central free layer. By suitable choice of the antiferromagnetic and ferromagnetic layer thicknesses, it is possible to separate the three magnetization switching fields and produce a staircase magnetoresistive curve. The maximum magnetoresistance (MR) ratio is 7.6% for current-perpendicular-to-plane and 6.3% for current-in-plane geometries with intermediate MRs of 3.9% and 3.0%, respectively. The use of exchange bias in a multistate memory device is discussed.