The observation of the magnetoresistance effect has been focussed on the
studies of the giant magnetoresistance (GMR) effect, throughout the world, by
researchers and scientists after its discovery from magnetic multilayer. It has later
been observed in granular alloys in which nanometer-sized magnetic granules such
as Co, Ni, Fe, are embedded in an immiscible metallic matrix (Ag, Cu, Au, etc.).
These magnetic alloys having GMR effect find potential applications in magnetic
field sensor and read heads.
In this work, granular thin films of CoAg and CoNiAg alloys have been
prepared using Radio frequency (RF) Magnetron sputtering technique. A split target
composed of high purity (99.99%) Co, Ni and Ag metals have been bombarded with
argon atoms to form plasma, which condensed onto the glass substrate to form thin
films of various thicknesses depending on the deposition time and RF power. The characteristics and magnetotransport properties of GMR materials based on the
CoAg and CoNiAg have been investigated. Magnetoresistance (MR) is usually
expressed as the fractional change in resistance of a specimen produced by an
applied field, GMR = MfR. For non-magnetic films MR is quite small, however the
presence of magnetic entities in the non-magnetic matrix, increases its MR .and
hence it is termed as GMR
