Nanostructure and magnetic properties of BN-encapsulated Fe(B) and Fe2N nanoparticles prepared by dual ion-beam sputtering

D. Babonneau, M. Jaouen, M.-F. Denanot, P. Guérin, F. Petroff
2003 Applied Physics Letters  
Ion-beam sputtering has been used to achieve the growth of FePt thin films and C/FePt granular multilayers at room temperature. The effects of thermal annealing on the structural and magnetic properties have been investigated by transmission electron microscopy, Rutherford backscattering spectrometry, grazing incidence X-ray diffraction, grazing incidence small-angle X-ray scattering, and magnetization measurements. The as-deposited films and granular multilayers show FePt grains (10-20 nm and
more » ... ains (10-20 nm and 2-3 nm in size, respectively) with a disordered face-centeredcubic structure and are magnetically soft. Thermal annealing at temperatures below 650 °C causes partial L1 0 ordering and growth of the FePt grains to 100-200 nm in the FePt films and to 5-8 nm in the C/FePt multilayers. Thermal annealing of the granular multilayers at 800 °C also results in the preferential graphitization of the carbon matrix and chemical interaction of the Fe atoms with the Si substrate. Magnetization measurements indicate that magnetic hardening occurs after annealing and that the saturation magnetization of the granular multilayers is strongly dependent on the annealing temperature.
doi:10.1063/1.1571230 fatcat:dvp6bpugozgfzjq33g2k4p6fhi