The A1 to L10 transformation in FePt and FeCuPt thin films:: Determination of isothermal transformation kinetics from nonisothermal measurements

Time-temperature-transformation diagrams describing the A1 to L1(0) transformation in 1 mu m thick FePt and FeCuPt alloy films are constructed from data obtained using nonisothermal differential scanning calorimetry in conjunction with a limited number of isothermal anneals. For the FePt alloys, an increase in Pt content from 45.6 to 52.5 at.% results in a >300x increase in the annealing time needed to reach a fraction transformed of 0.95 at 300 degrees C. Using geometric corrections, the results are extended to 10 nm thick films, which are found to transform approximately five times more slowly than thicker films. (C) 2006 American Institute of Physics.