Successive spin reorientation and magnetostriction in (Er/sub 1-x/Tb/sub x/)/sub 2/Fe/sub 14/B

Magnetostriction measurements in highly-oriented melt-spun ribbons of (Er/sub 1-x/Tb/sub x/)/sub 2/Fe/sub 14/B with 0/spl les/x/spl les/0.45 have been performed in order to investigate the lattice deformation at the spin reorientation (SR) transitions. The c-axis of the tetragonal cell was found to be aligned perpendicular to the ribbon plane. The sum of the longitudinal and transverse magnetostriction /spl lambda//sub ///+/spl lambda//sub /spl perp//, with fields applied within the ribbon plane, was a maximum at successive SR temperatures. A model calculation of the volume change /spl Delta/V/V was made by assuming that only the lowest order crystalline electric field potentials at Er and Tb sites affect the volume change. This calculation showed that /spl Delta/V/V exhibits a sharp peak at the SR temperatures, which is in accordance with the experimental peaks of /spl lambda//sub ///+/spl lambda//sub /spl perp//.