Anomalies of magnetostriction and thermal expansion in Nd 6Fe 13Si solid solution

Abstract

In this research, we have studied magnetoelastic interactions in Nd 6Fe 13Si solid solution by magnetostriction and thermal expansion measurements. Magnetostriction versus temperature in the range of 77–300 K show that by rising temperature above 115 K, the sign of magnetostriction changes from negative to positive, which indicates a rapid expansion of the sample. This sign reversing is accompanied by a spin re-orientation of iron ions from basal plane of tetragonal unit cell to c-axis at higher temperatures. At the spin re-orientation temperature ( T sr) of 115 K, where the two spin arrangements coexist with equal probability, magnetostriction remains around zero. This is due to the compensation of the negative magnetostriction of the low-temperature phase by positive magnetostriction of the high-temperature phase. The magnetostriction compensation effect appears as a peak in the thermal expansion coefficient curve.