Magnetoanisotropy, long-range order parameter and thermal stability of isolated L10 FePt nanoparticles with mutual fixed orientation

Oriented L10-FePt nanoparticles with mean sizes as small as 12nm have been fabricated by electron beam evaporation. Atomic order parameter evaluated was as low as 0.55±0.02 in spite of the long-time annealing as long as 86.4ks at 873K. Magnetoanisotropy constant was estimated to be 1.2-1.4×106J/m3, which was much smaller than that of bulk FePt. Residual magnetization showed a decay of about 3-4% at 300K. The relatively small values of magnetoanisotropy are closely related to the small order parameter, and thought to be responsible for residual magnetization decay at 300K. © 2003 Elsevier B.V. All rights reserved.