Mechanisms of spontaneous magnetostriction in Nd(Fe,Mo)12 and YFe10Mo2 compounds with various magnetic anisotropy

The temperature dependences of thermal expansion coefficient (5-900 K) and initial magnetic susceptibility (5-300 K) were investigated for NdFe12-xMox ( x = 1.3; 1.5; 2.0) and YFe10Mo2 compounds with axial, conical or planar anisotropy and spin orientation transition in a compound with x = 1.3 at 160 K. Magnetic contribution to thermal expansion coefficient is shown to constitute a sum of three compounds, namely, a contribution from molecular field; a Schottky contribution associated with splitting of Nd3+ basic state in crystalline field; a contribution associated with variation of magnetic moment of Fe atoms. Spontaneous volume magnetostriction is found to vary from 1.3 to 0.8% and to depend slightly on the type of magnetic anisotropy. 17 refs.; 4 figs