Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8152754 | Journal of Magnetism and Magnetic Materials | 2018 | 12 Pages |
Abstract
The face- centered- tetragonal (FCT) or L10 phase of Fe50Pt50 (FePt) film is obtained on annealing FePt films at high temperature (â¼600â¯Â°C), that usually grows as face-centered- cubic (FCC) phase. Cu as an additive up to â¼20 atomic%, which form ternary alloy FePtCu on mixing, is used to reduce the ordering temperature. We studied the formation of FePtCu ternary alloy: its structure, magnetic properties and grain growth at the interfaces of a FePt/Cu multilayer, as a function of annealing temperature (100â¯Â°C-600â¯Â°C), which is very less as compared to their melting temperatures. The study indicates the growth of a ternary alloy with composition of (FePt)0.42Cu0.58 in FCT phase on annealing the FePt/Cu multilayer at a moderate annealing temperature (â¼400â¯Â°C). With a large addition of Cu at 56 atomic% in FePt, the ordering temperature reduces by â¼200â¯Â°C and form a ternary alloy with distinct magnetic properties. We observed rapid growth of ordered FCT phase with increase in crystallite size from 50â¯Ã
to 150â¯Ã
on annealing the multilayer in the range of 400â¯Â°C-600â¯Â°C. Interestingly, from macroscopic magnetization measurements we could identify the existence of a super-paramagnetic (SP) phase at room temperature with a typical particle size of â¼12â¯Ã
of ternary alloy on annealing the multilayer at 400â¯Â°C, which is much smaller than the crystallite size (â¼50â¯Ã
). Annealing at 600â¯Â°C reduces the multilayer to a disordered magnetic phase. The room temperature SP nanoparticles of FePtCu alloy phase formed on annealing the multilayer at 400â¯Â°C are potential candidates in biomedical applications.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
Surendra Singh, C.L. Prajapat, M. Gupta, S. Basu,