Magnetostriction in Ni rods under torsion: Critical stress and crystal anisotropy effect

A contribution to the investigation of the stress effect on the saturation magnetostriction of polyerystalline rods stressed by torsion is presented. The critical torsional stress above which magnetostriction remains constant is found and the crystal anisotropy level, at various torsions, is estimated. As in the tensional case, the effect of crystal anisotropy at the critical stress has not been clearly interpreted so far. A study of the behaviour of the magnetization curve near saturation provides a possible explanation.