Control of Crystallographic Domain by Magnetic Field in Ferromagnetic Shape Memory Alloys and an Antiferromagnetic CoO

摘要

We have investigated the rearrangement of crystallographic domains (variants) driven by magnetic field in three kinds of ferromagnetic shape memory alloys of Fe-31.2Pd (at.%), Fe_3Pt (S=0.8) and Ni_2MnGa and an antiferromagnetic oxide of CoO, and have evaluated the values of the shear stress driven by magnetic field (magnetic shear stress, τ_(mag)) acting across the twinning plane and the shear stress required for the twinning plane movement, τ_(req). As a result, we have confirmed the propriety of the condition for the rearrangement of crystallographic domains driven by magnetic field, that is, when τ_(mag) is larger than τ_(req), the rearrangement occurs irrespective of the magnetism of materials.