Highly (001) oriented thin films of Co2 MnSi have been grown on lattice-matched GaAs(001) without a buffer layer. Stoichiometric films grown at the highest substrate temperature of 689 K showed the lowest resistivity (33 μΩ cm at 4.2 K) and the lowest coercivity (14 Oe). Twofold in-plane magnetic anisotropy was observed due to the inequivalence of the 〈110〉 directions, and this was attributed to the nature of the bonding at the reconstructed GaAs surface. Interfacial reactions resulted in the formation of an epitaxial Mn-As region and a thin interfacial layer that was Co-Ga rich. This prevented the desired lattice matching and resulted in films with a saturation magnetization slightly below the bulk value. In spite of this, the spin polarization of the free surface was measured to be 55%, similar to bulk material.
ASJC Scopus subject areas
- Physics and Astronomy (all)