EFFECT OF PRESSURE ON THE MAGNETOCRYSTALLINE ANISOTROPY OF (ERXR1-X)2FE14B INTERMETALLICS

A systematic study of the effect of pressure up to 1 GPa on the spin reorientation transition (SRT) phenomena has been performed on several series of pseudo-ternary compounds (ErxR1-x)2Fe14B for R = Nd, Gd, Dy and Y using a low-field AC susceptibility technique. The variation in the SRT temperature T(SR) under pressure has been used as an indication of the effect of the pressure on the crystal electric field (CEF) at the rare-earth ion site. We have observed that the pressure effect on the Er2Fe14B compound (DELTAT(SR)/DELTAp = -20 K GPa-1) was not affected by the substitution of Er by Gd and Y ions. A completely different high-pressure behaviour has been observed for the (ErxDY1-x)2Fe14B and (ErxNd1-x)2Fe14B compounds, in which the variation in T(SR) under pressure decreases for increasing content of Dy and Nd. This different behaviour has been attributed to the strong influence of pressure on the CEF interactions. Using these results we have determined the variation in the CEF parameters under applied pressure.