パルス電析によるFe-Ni系微粒子・多層膜の電気的および磁気的性質

Abstract

Pulse electrodepositon is a useful technique with which it is possible to achieve atomic-scale control of the layer composition, thickness of the multilayer and the grain size in ferromagnetic films by regulating the pulse amplitude and width. It is possible to fabricate ferromagnetic films with various magnetic properties from a single electrolytic solution containing more than two kinds of metallic ions, by changing the step pulse wave. Multilayer films composed of a Ni-rich layer with high coercive force, an Fe-Ni layer with low coercive force, and a nonmagnetic Cu layer were produced by controlling the step pulse potential from a single electrolytic solution containing Fe, Ni and Cu ions. Moreover, we are able to produce thinner ferromagnetic films consisting of multiple layers with magnetic characteristics such as a wide variation in coercive force, high susceptibility, and large magnetoresistance effect by controlling the time interval of the step pulse.In this study, we investigated the relationships between the magnetic field dependence of the magnetoresistance effect and the film preparation conditions for composition-modulated Fe-Cu-Ni alloy films produced by the pulse electrodeposition method. The MR ratio observed in the film has maximum values of 3.4% and 9% at 300 K and 5 K, respectively. A highly sensitive change of the electric resistance was obtained at a low magnetic field.