Insights into Growth of Fe₇Pd₃ Ferromagnetic Shape Memory Alloy Thin Films

Abstract

Single crystalline-like thin film samples of the ferromagnetic shape memory alloy Fe7Pd3 enable studying the physics of this promising material system. We demonstrate how to grow such samples with electron beam evaporation and investigate the influence of variable deposition parameters, focusing hereby on substrate temperature and deposition interruptions. We are able to produce Fe7Pd3 thin film samples of 500 nm in thickness in austenitic and martensitic phases and the latter with twinning structures visible at the sample surface. The ideal substrate temperature turns out to be around 700 °C, whereas deposition at temperatures below 690 °C leads to sample demixing, while film quality is decreased at higher temperatures because of lattice misfit effects. In the case of direct substrate heating by heat radiation, comparable sample quality is accomplishable if numerous deposition interruptions are included in the growth procedure to homogenize surface temperature so that comparable effective material diffusion, i.e., material relaxation, is achieved. Our investigations resulted in identifying a quite easily realizable deposition procedure to grow samples of satisfyingly good quality with closed surfaces and without the need for subsequent processing.