MAGNETORESISTANCE PROPERTIES OF FE-NI INVAR ALLOY EVAPORATED-FILMS

The orientational magnetoresistance effects (DELTArho) in as-deposited Fe-33% Ni films with thicknesses in the range 170-450 angstrom deposited onto fused quartz (SiO2) has been investigated. DELTArho increased with decreasing film thickness though the magnetization decreased. On the other hand, in as-deposited alpha/gamma-Fe-Ni coupled films with alpha-phase Fe-9% Ni and gamma-phase Fe-33% Ni, the magnetization was unchanged though the B-H loop was changed. However, in alpha/gamma-Fe-Ni coupled films annealed at 600-degrees-C (30 min) the orientational effect is enhanced in comparison with the case of as-deposited films, in which the B - H form is remarkably changed and the magnetization is reduced by about 17%. The singularity of the magnetoresistance effect can be attributed to the spatially inhomogeneous magnetic structure having a different magnetic component and a different exchange interaction between neighbouring interfaces.