Magnetic anisotropy in FexPd1-x (x = .30, .44, .55, .67, and .78) alloy film grown on SrTiO3(001) and MgO(001) by molecular beam epitaxy

摘要

FexPd1-x (x = .30, .44, .55, .67, and .78) films were directly grown on SrTiO3(001) and MgO(001) by molecular beam epitaxy at 500 C. The thickness of all films is 50 rim. X-ray diffraction shows epitaxial quality and face-center- tetragonal (001), (002), and (003) peaks indicating an FePd L1(0) order state for films of x = .30, .44 and .55. X-ray diffraction only shows (002) peaks with a relatively weak intensity for the film of x =.67 and no (001) peak is observed, but a broad body-center-cubic Fe(002) is identified for the film of x = .78. Magnetic hysteresis curves are carried out by a vibrating sample magnetometer (VSM) with an applied field within 12 kOe. Magnetization of both in-plane and perpendicular-to-the-plane measurements show a linear increase of the magnetization saturation from 560 emu/cm(3) to 1250 emu/cm(3) as x increasing from .30 to .78. For the results of the in-plane measurements, remanence (M-r), however, shows a minimum while the anisotropy field (H-k) shows a maximum for the film with x = .44 indicating the optimal content ratio of Fe/Pd for perpendicular anisotropy in the present alloy films. Further, negative remanence is observed in the hysteresis curves where the field is perpendicular to the film of x = .78 This may indicate that the L1(0) order state still affects the magnetic anisotropy for high Fe content films even though the film has a body-center-cubic structure.