Rearrangement of crystallographic domains driven by magnetic field in Fe3Pt and CoO and new phase appearance in Ni2MnGaT. Kakeshita, T. Terai, M. Yamamoto and T. Fukuda
Department of Materials Science and Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-Oka, Suita, Osaka 565-0871, Japan
Published online: 1 September 2009
We have investigated the rearrangement of crystallographic domains driven by magnetic field in a ferromagnetic shape memory alloy of Fe3Pt and an antiferromagnetic oxide of CoO. Also, we have determined the equilibrium stress-temperature phase diagram in a ferromagnetic shape memory alloy of Ni2MnGa. Following results are obtained ; (i) We confirm that magnetic field promotes the rearrangement of crystallographic domains in Fe3Pt and CoO and the condition of the rearrangement in the present two systems is the same, that is, the magnetic shear stress, which corresponds to the magnetic anisotropy energy divided by the twinning shear, is equal to or larger than the twinning stress. (ii) We construct the equilibrium stress-temperature phase diagram of Ni2MnGa by compressive tests and magnetic susceptibility measurements, and show the existence of the new phase of X-phase. Moreover, we evaluate the triple point at which the I-, P- and X-phases coexist and suggest the existence of a critical point of the successive P → X → I transformation.
Note to the reader:
On pages 04008-p1, 04008-p2, 04008-p3 and 04008-p6 several mistakes have been corrected on October 19, 2009.
© Owned by the authors, published by EDP Sciences 2009