The effect of stress bias on the magnetic and magnetomechanical properties of tb_xho_1-nfe_1.9, 0 < x < 0.2

Abstract

The quasi-static magnetic and magnetomechanical properties of Tb_xHoi._xFei 9 have been studied at room temperature, as a function of stress bias, over the composition range 0 < x < 0.2, within which the easy axis changes between ⟨100⟩ and ⟨111⟩. In both easy axis regimes, the saturation strain increases with increasing stress bias, and the saturation magnetisation is independent of stress bias. In the ⟨111⟩ easy regime, the magnetisation process changes from a mixture of domain wall motions followed by rotation with no applied stress, to a single 180° wall motion followed by rotation when stress is applied. In the ⟨100⟩ easy regime, applied stress levels < 20 MPa favour the movement of 90° walls and produce increased negative magnetostriction. Stress values > 70 MPa produce only positive magnetostriction. Unlike the ⟨111⟩ easy regime, the shape of the magnetisation curves is invariant under stress bias because the value of magnetisation at which rotation commences is constant.