Site occupancy and magnetic moment of Fe in Ni2Mn0.3Fe0.7Ga alloy by neutron powder diffraction study

Abstract Neutron powder diffraction measurements were carried out in a wide temperature range from 14 to 500 K for Ni 2 Mn 0.3 Fe 0.7 Ga alloy, which undergoes a martensitic transformation from L 2 1 -type austenite phase to four layered orthorhombic-type martensite phase at about 160 K during cooling. For the diffraction pattern measured at 500 K in the paramagnetic austenite phase, it was clarified that the Mn and Fe atoms randomly occupied 4 a site in the L 2 1 -type structure. Magnetic moments of Ni, Mn and Fe in the ferromagnetic austenite phase at 200 K were decided to be 0.3 and 3.3 and 3.0 μ B , respectively. The magnetic moment of Fe is significantly larger than that in pure bcc-Fe of 2.2 μ B . Magnetic moments of Fe in two sites at 14 K in the martensite phase were obtained to be 2.3 and 2.6 μ B , respectively, suggesting that the comparatively large magnetic moments of Fe were kept even in the martensite phase. Total magnetic moment of the martensite phase at 14 K from the neutron powder diffractive analyses is 3.7 μ B /f.u., being in good agreement with the result of the magnetic measurement of 3.5 μ B /f.u. at 4.2 K.