Tetragonal D0₂₂Mn3+xGe Epitaxial Films Grown on MgO(100) with a Large Perpendicular Magnetic Anisotropy

First-principles calculation of D022 Mn3Ge shows a fully spin-polarized Δ1 band at the Fermi level, low saturation magnetization MS=180 emu/cm3, high uniaxial magnetic anisotropy Ku=23 Merg/cm3, and low Gilbert damping α=9×10-4. We also experimentally investigate D022 Mn3+xGe epitaxial films grown on MgO(100) substrates with different compositions x. The films exhibit a coercivity of about 20 kOe, MS of about 130 emu/cm3, and Ku of about 10 Merg/cm3 at x=0.55 (78 at.% Mn). These indicate that D022 Mn3Ge is a good candidate for spin-transfer-torque random access memory.