The growth, structure and some magnetic properties of epitaxially grown nickel-iron films

Abstract

This thesis describes the epitaxial growth of thin films of binary nickel-iron alloys in the composition range 60% Ni to 75% Ni, the study of their structure, and a brief investigation of the magnetic properties of some of the films. Most of the work was directed towards obtaining the alloys in the form of high purity, parallel-sided, single-crystal, thin films. A series of films was deposited by condensation from the vapour phase on to the principal planes of rocksalt maintained at elevated temperatures in a vacuum of 10mm Hg pressure. Examination of these films in the electronmicroscope revealed that epitaxial growth was possibleunder certain conditions but that the films were aggregated,had a high density of twins and stacking faults and showeda wide variation in crystallite size. Some films depositedon (110) rock salt faces had a particularly interestingstructure. A further series of alloy films was deposited,this time on to continuous films of copper (freshly epitaxedon to the principal planes of rock salt); these alloy filmswere excellently oriented, continuous down to about 100 A thickness and more easily reproducible. Concurrently with the above a hysteresis loop plotter was built; details are given of the construction, calibration and use of thisinstrument. The brief magnetic investigations were concentrated upon (110) type films in the low magneto-crystalline anisotropy region of the 65% Ni 35% Fe alloy. Film thicknesses were determined by colorimetric microchemistry.