Rapid ordering of Zr-doped FePt alloy films

The magnetic properties and microstructural evolution of Zr-doped FePt alloy films prepared by dc-magnetron sputtering were investigated. Compared to an undoped Fe59Pt41 binary film, Zr-doped FePt alloy films showed accelerated ordering transformation kinetics accompanying smaller grains: we were able to fabricate a Zr-doped FePt film [e.g., (Fe59Pt41)(97)Zr-3] possessing very fine grain size (5 nm in average) and high coercivity (7.3 kOe) within 10 min annealing at 500 degreesC. It is thought that the point defects and lattice strain introduced by Zr-doping activated the nucleation rate of the ordered phase. In particular, for Zr-doped FePt films containing less than 45 at. % Pt, the ordered L1(0) phase was decomposed into a disordered phase after excessive annealing due to the formation of a Pt-Zr compound, most likely Pt3Zr, that reduces the effective Pt content in the ordered phase. (C) 2001 American Institute of Physics.