Magnetism and magnetocaloric effect of melt-spun, nanostructured GdAl2

Abstract

Magnetocaloric effect (MCE) of melt-spun rare earth intermetallic compound GdAl _2 (Cubic, MgCu _2 -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 (T _C ) of about 136 K. This value is about 30 K lower than the ferromagnetic transition temperature of the arc-melted GdAl _2 . The maximum isothermal magnetic entropy change (ΔS _m ) is found to be ∼ −8.3 Jkg ^−1 K ^−1 at 133 K for 70 kOe field change around T _C . 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.

Keywords

• magnetic properties
• magnetocaloric effect
• are earth intermetallics
• melt-spinning