Epitaxial Heusler alloy Co_2FeSi films on Si(111) substrates grown by molecular beam epitaxy

摘要

The influence of growth temperature on the structural and magnetic properties of Heusler alloy Co_2FeSi films grown on Si(1 1 1) substrates has been studied. Reflection high energy electron diffraction, double crystal x-ray diffraction (DCXRD) and transmission electron microscopy (TEM) measurements revealed that Co_2FeSi layers were epitaxially grown on Si(1 1 1) substrates in an optimized growth temperature range 150 °CT_G 200 °C. From DCXRD measurements and TEM, it was shown that in the optimized temperature range the Co_2FeSi/Si(11 1) films crystallize in the B2 + L2_1 structures. All layers are ferromagnetic and well-ordered films on Si(11 1) show high magnetic moments with an average value of (1140 ± 250) emu cm-3, which is in good agreement with the value of bulk Co_2FeSi at 300 K. The magnetic anisotropy is correlated with the structural properties of the layers.