Structural, magnetic and electrical properties of Fe/Cu/Fe films

Abstract

A set of sandwich films in the configurations, Fe(200 nm)/Cu(t)/Fe(200 nm); t = 20 nm, 40 nm, 60 nm, 80 nm, 100 nm and 200 nm have been grown using thermal and electron beam gun evaporation techniques at a temperature of 473 K, under high vacuum conditions. The structure and crystallite sizes of the films were investigated by grazing incidence X-ray diffraction (GIXRD). The microstructure was examined by scanning electron microscope (SEM) studies. Average grain size and surface roughness were determined by atomic force microscope (AFM). The room temperature magnetization as a function of field has been measured using the vibrating sample magnetometer (VSM). The results revealed the existence of antiferromagnetic (AF) coupling between Fe layers through an interfacer Cu layer. The strength of AF coupling was observed to be increasing with increasing t and became maximum for t = 60 nm and, decreases for further increase in t. The behavior of coercive field with t indicated softness of the films. The low temperature electrical resistivity in the range from 4.2 K to 300 K has been measured. The residual resistance ratio, RRR and the temperature coefficient, TCR were determined. The power laws for the resistivity variation with temperature have been established. This is for the first time that a set of sandwich films in the present configurations were investigated for structural, magnetic and electrical properties and, the power laws for resistivity variation at low temperature have been established. © 2010 Elsevier Ltd. All rights reserved.