Electrodeposition of coercive L1(0) FePt magnets

We report the preparation, characterization of structure and magnetic properties of electrodeposited L1₀ FePt films with high coercivity. Equiatomic as-deposited films are nanocrystalline, soft and magnetically isotropic. The transition from the disordered to the ordered phase was studied by varying the annealing time and annealing temperature. The as-deposited nanocrystalline deposits were treated in forming gas and developed the tetragonal L1₀ structure only at temperatures above 500 °C. The coercivity increases with both annealing temperature and annealing time reaching a value of 1.5 T at 900 °C. The magnetization reversal mechanism was identified as nucleation type from the initial magnetization curve of a thermally demagnetised sample.