Barrier dependence of magnetoresistance enhancement in nano-oxide added spin valves

Abstract

The effects of different types of nano-oxides on the properties of spin valves have been studied. The nano-oxides that have been investigated in this study include NiFe-O, Al-O, CoFe-O, Ta-O, and Cu-O. From the point of view of overall properties (magnetoresistance ratio, change of sheet resistance, exchange coupling field, and interlayer coupling field), CoFe-O turned out to be the most desirable oxide when being used as the bottom oxide for top spin valves. As a capping layer for bottom spin valves, however, it was found that Al-O is the best choice among those investigated. Under optimum conditions, IrMn-based dual spin valves with a magnetoresistance ratio up to 21.8% has been successfully fabricated by incorporating oxide layers in both pinned ferromagnetic layers.© 2002 American Institute of Physics.