Magnetostriction and heat-capacity study on the metamagnetic phase transition of Dy2In1-xAlx alloys

Abstract

In Dy2In1-xAlx (x = 0, 0.2, 0.3 and 0.4) alloys, the hexagonal structure is gradually transformed into orthorhombic one with x = 0.3 as the critical composition. In Dy2In0.7Al0.3 alloy, the highest magnetic entropy change is accompanied with highest saturation magnetostriction ∼995 ppm under 7 T near phase transition temperature, indicating the typical strong magnetoelastic coupling. From heat-capacity (Cp) measurement, a sharp peak is observed on the Cp - T curves for Dy2In1-xAlx (x = 0, 0.2 and 0.3) alloys. Meanwhile, more Al substitution for In leads into the reduced density of state near Fermi level of each alloy judged from Cp/T - T2 curves. The maximized ΔTad for a field of 7 T is slightly increased from 6.5 K in Dy2In to 7 K in Dy2In0.7Al0.3.