LAUSR

Abstract We investigated crystalline orientation dependence of magnetostriction of twinned rhombohedral perovskite cobalt oxide, La0.8Sr0.2CoO3. The magnetostriction in a magnetic field applied along the pseudo-cubic [ 111 ] c and [ 110 ] c axes showed large hysteresis and residual strains. On the other hand, hysteresis and residual strain were not observed in the applied magnetic field along the [ 001 ] c axis. The large hysteresis and residual strains of the magnetostriction along the [ 111 ] c and [ 110 ] c axes are successfully interpreted as a rearrangement of the rhombohedral domains with the magnetocrystalline hard axis along the rhombohedral [ 111 ] r . The no hysteresis and no residual strain of the magnetostriction along the [001]c axis are interpreted by equal projection to [001]c axis of [111]r of all the domains. The twinned structure of La0.8Sr0.2CoO3 with the magnetic anisotropy qualitatively accounts for the crystalline-orientation dependence of the magnetostrictions.