STRUCTURAL, MAGNETIC AND MAGNETOSTRICTIVE STUDIES OF TB0.27DY0.73(FE1-XALX)2

Measurements of magnetic properties, X-ray diffraction and magnetostriction were made on Tb0.27Dy0.73(Fe1-xAlx)2 (x = 0.1, 0.2, ..., 0.7) compounds. It was found that the system has the cubic MgCu2 structure over almost the whole (Fe,Al) concentration range investigated, except for a narrow intermediate range (x = 0.4-0.6) where the hexagonal MgZn2 structure appears. With increasing Al content x, the lattice constant a increase linearly with x. The first replacement of Fe results in a marked decrease in the Curie temperature, which is followed by a slight decrease in T(C) with x. A linear decrease in magnetostriction of \lambda(parallel-to) - lambda(perpendicular-to)\ at room temperature with x was also observed from 1530 x 10(-6) for x = 0 to 36 x 10(-6) for x = 0.3. The saturation magnetization sigma(s) exhibits a complex concentration dependence in the Tb0.27Dy0.73(Fe1-xAlx)2 system: in the range x < 0.5, sigma(s) increases linearly with x and, for x = 0.5-0.6, sigma(s) decreases and then increases again. An enhancement of the magnetic 'hardness' in this system was also observed at low temperature.