Abstract
Giant magnetoresistance(GMR)characteristics of NiFe/Cu/Co spin valve thin films, which were formed on Cu/Si(111, 4 degree tilt-cut)templates by a 3-gun magnetron sputtering system, have been investigated as a function of composition in NiFe layer. It was found that R-H curves of these thin films change drastically with the composition in NiFe layer so that perfectly square R-H curves were obtasined at 4 : 1 atomic ratio of Ni : Fe and sloped R-H curves at zero external magnetic fields were obtained at other atomic ratios of Ni : Fe. The change of R-H curves could be understood by a transition of magnetic anisotropy in NiFe layer with the compositional variation. Analysis of crystal structures and preferred orientations by pole figure measurement indicate that the changes of magnetic anisotropy and GMR characteristics are originated from the variation of magnetoelastic effect of thin films. It was believed that these various GMR characteristics could increase the potentials of NiFe/Cu/Co spin valve thin films for recently researched magnetic devices.
