Stress dependence of ferromagnetic resonance and magnetic anisotropy in a thin NiMnSb film on InP(001)

The authors have investigated the effect of stress on the room-temperature magnetism of a 10nm thick Heusler-alloy film NiMnSb grown epitaxially on InP. Tensile stress, which the authors applied externally along the easy axis using a piezostack, is shown to reduce the coercivity and the anisotropy coefficient. Using broadband ferromagnetic resonance measurements, the authors find that a relative variation in the lattice constant as small as 0.08% changes the in-plane uniaxial anisotropy by 20%. This explains the significant variation of anisotropy with film thickness, which was recently reported for NiMnSb.