STRUCTURAL, MAGNETIC, MAGNETOSTRICTION AND MAGNETOMECHANICAL STUDIES ON HO0.85TB0.15FE2-XALX LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.2) ALLOYS

X-ray diffraction studies carried out on the Ho0.85Tb0.15Fe2-xAlx (0 l ess than or equal to x less than or equal to 0.2) system revealed that all the compositions investigated retained the C-15 cubic Laves phase structure. The field dependence of the magnetization has been measure d in the temperature range 300 K less than or equal to T less than or equal to 700 K and that of magnetostrictive strain at room temperature . Incremental relative permeabilities and magnetomechanical coupling c oefficients have been obtained as a function of external static magnet ic field, at room temperature. A comparison of the magnetostrictive re sponses indicates that the saturation magnetostriction, as well as the magnetomechanical coefficient, decreases with increasing aluminium co ncentration. A slight lowering of the dynamic strain coefficient with Al content is attributed to a reduction in magnetoelastic coupling, al so seen in a lower magnetomechanical coupling coefficient. The Curie t emperature values have been found to reduce with increasing Al concent ration, which may be due to either the slight increase in lattice para meter or the weakened RE-TM and TM-TM interactions when Fe is partiall y substituted by Al.