Magnetism and magnetocaloric effect of melt-spun, nanostructured GdAl2

Abstract

Magnetocaloric effect (MCE) of melt-spun rare earth intermetallic compound GdAl2 (Cubic, MgCu2-type) has been studied. The sample becomes nanostructured upon melt-spinning and the crystallite size obtained from the powder x-ray diffraction data is about 48 nm. A sluggish paramagnetic to ferromagnetic transition occurs at a Curie temperature (TC) of about 136 K. This value is about 30 K lower than the ferromagnetic transition temperature of the arc-melted GdAl2. The maximum isothermal magnetic entropy change (ΔSm) is found to be ∼ −8.3 Jkg−1 K−1 at 133 K for 70 kOe field change around TC. This value is quite comparable to that of bulk sample prepared by arc-melting which is about −8.5 Jkg−1 K−1 at 168 K for the same field change. Thus melt-spinning process results in broadening of the peak in the isothermal magnetic entropy change versus temperature plot without compromising on the magnetocaloric effect.