Successive magnetic transitions and magnetocaloric effect in Dy3Al2 compound

Abstract

Magnetic properties and magnetocaloric effect (MCE) of intermetallic Dy3Al2 compound have been investigated systematically. Two successive magnetic transitions, a paramagnetic–ferromagnetic transition at TC = 94 K followed by a spin reorientation around TSR = 69 K, are observed with the variation of temperature. Large permanent magnetic properties at low temperatures, i.e., the coercivity Hci and maximum energy product (BH)max at 5 K are 26.0 kOe and 58.5 MGOe, respectively, suggest Dy3Al2 compound as attractive candidate for low-temperature permanent magnets. For a magnetic field change of 50 kOe, two successive magnetic entropy change (ΔSM) peaks of 5.2 and 12.1 J/kg K are observed around TSR and TC, respectively. These two ΔSM peaks overlap partly, and thus giving rise to a high refrigerant capacity (RC = 360 J/kg at 50 kOe) over a wide temperature span. The universal curve of successive ΔSM peaks is constructed by using a phenomenological procedure. It is found that not only the curves under different magnetic field changes but also the curves around different transitions collapse onto the nearly same universal curve. Our result suggests that the phenomenological construction of universal curve is applicable in materials with successive second-order phase transitions.