Epitaxial growth of ferromagnetic Ni2MnGa on GaAs(001) using NiGa interlayers

Heusler alloy Ni2MnGa thin films have been grown pseudomorphically on a relaxed NiGa interlayer on GaAs(001) by molecular-beam epitaxy. In situ reflection high-energy electron diffraction patterns, ex situ x-ray diffraction, and cross-sectional view transmission electron microscopy electron diffraction patterns confirm the single-crystal growth of Ni2MnGa. The films grow pseudomorphically on the relaxed NiGa interlayer with a tetragonal structure (a=b=5.79 A and c=6.07 A). Magnetic measurements using vibrating sample and superconducting quantum interference device magnetometers reveal Ni2MnGa to have an in-plane easy axis and a Curie temperature ∼350 K.