Thin film structures for low field granular giant magnetoresistance

Abstract

Giant magnetoresistance (GMR) is a relatively new field of study pursued by scientists and technologists alike. A potential application of GMR thin films is the replacement of NiFe alloy thin films (having anisotropic magnetoresistance) to obtain greater signal. Applications of this type require that the GMR be obtained at low fields, on the order of 10 Oe. In this paper three types of granular GMR thin film structures are described: co-deposited heterogeneous alloys, granular bi-layers, and discontinuous multilayers. Experimental examples of each type are presented, and the field dependence of GMR for each structure is discussed. Only discontinuous multilayer thin film structures have shown suitable GMR at low fields, and the properties and microstructure of these thin films will be described in greater detail.