Epitaxially grown Cu₂Sb-type MnGaGe films with large perpendicular magnetic anisotropy

A perpendicularly magnetized film is essentially important for spintronics applications, such as spin-transfer-torque type magnetoresistive random access memories, STT-MRAMs, and large perpendicular anisotropy energy, K u, with small saturation magnetization, M s, is required for reducing the critical current for the STT induced magnetization switching phenomenon. In this study, an equiatomic intermetallic compound, MnGaGe, was investigated in epitaxially grown film samples. Perpendicularly magnetized films with an M s value of about 260 emu/cm³ at 300 K were fabricated onto MgO (100) single crystal substrates. The maximum value of K u was 8.1 × 10⁶ erg/cm³ at room temperature. Microstructure analysis using a scanning transmission electron microscope atomically revealed the Cu₂Sb type crystal structure in the film sample. First principles calculations were also carried out to discuss the electronic structure. Using the analysis of the projected density of states for 3d-orbitals, the hybridization of the 3d-orbitals was suggested as a possible factor for promoting magnetocrystalline anisotropy. The MnGaGe film with the large K u and relatively small M s would be potentially used for spintronics applications.