6533b870fe1ef96bd12cf9ec

RESEARCH PRODUCT

Epitaxial film growth and magnetic properties ofCo2FeSi

subject

description

We have grown thin films of the Heusler compound ${\mathrm{Co}}_{2}\mathrm{Fe}\mathrm{Si}$ by RF magnetron sputtering. On (100)-oriented MgO substrates we find fully epitaxial (100)-oriented and $L{2}_{1}$ ordered growth. On ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}(11\overline{2}0)$ substrates, the film growth is (110)-oriented, and several in-plane epitaxial domains are observed. The temperature dependence of the electrical resistivity shows a power law with an exponent of $7∕2$ at low temperatures. Investigation of the bulk magnetic properties reveals an extrapolated saturation magnetization of $5.0{\ensuremath{\mu}}_{B}∕\mathrm{f.u.}$ at $0\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The films on ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ show an in-plane uniaxial anisotropy, while the epitaxial films are magnetically isotropic in the plane. Measurements of the x-ray magnetic circular dichroism of the films allowed us to determine element specific magnetic moments. Finally we have measured the spin polarization at the surface region by spin-resolved near-threshold photoemission and found it strongly reduced in contrast to the expected bulk value of 100%. Possible reasons for the reduced magnetization are discussed.