Magnetostriction of paramagnetic rare earth orthoaluminates

Abstract We report the experimental and theoretical study of the magnetostriction (MS) in orthoaluminates with Ising rare earth (RE) ions, TbAlO 3 , DyAlO 3 and also with an S-ion, GdAlO 3 . The field and the temperature dependence of the MS is found to depend strongly on the nature of the RE ion ground state. In the case of GdAlO 3 , with L = 0 for the Gd 3+ ion ground state, the MS behaviour is basically described well by the formulae of the phenomenological even effects theory. A microscopic theory predicts a specific dependence of the MS on H and T for the orthoaluminates TbAlO 3 and DyAlO 3 , in which the RE ions Tb 3+ and Dy 3+ can be treated as Ising ions. The MS of the crystals with Tb 3+ and Dy 3+ exhibits a strong field dependence in the magnetization saturation region. Generally speaking, these crystals do not obey the phenomenological theory of even effects. Experiments on TbAlO 3 and DyAlO 3 confirm fully these conclusions.