Stacking Faults Induced Domain Wall Pinning in (001) FePd Thin Film

摘要

FePd (001) films, prepared by an electron beam deposition system on MgO(100), exhibit a perpendicular magnetic anisotropy$(1.7imes 10^{7} ext{erg}/ext{cc})$with a high order parameter (0.92). The strain relaxation process in epitaxially grown thin-film is pretty common [1] and the strain relaxed induced defects were detailed analysed by high resolution transmission electron microscope(HRTEM), as shown in Fig. 1(a)-(c). The relation between stacking faults induced by the strain relaxation, which act as strong domain wall pinning sites, and perpendicular coercivity$(mathrm{H}_{mathrm{c},perp})$of FePd films prepared at 400-700°C have been investigated. The variation of$mathrm{H}_{mathrm{c}}$is shown in Fig. 1(d).$mathrm{H}_{mathrm{c},perp}$can be enhanced via raising the stacking fault densities, which can be promoted by climbing dissociation [2]. The increased stacking fault densities with large$mathrm{H}_{mathrm{c},perp}(6ext{kOe})$is obtained for samples prepared at 650 °C. On the other hand,$mathrm{H}_{mathrm{c},perp}$drops significantly prepared at 700°C and treated with post-annealing at 700°C for 5hs, resulting from reducing stacking fault density. This result suggests the coercivity can be manipulated via controlling stacking fault density in FePd film, which may pave a way for future magnetic devices.