Large low-field magnetic entropy changes in as-cast Hf0.83−xZrxTa0.17Fe2 compounds

Series of Hf0.83−xZrxTa0.17Fe2 (x=0, 0.1, 0.2, and 0.3) compounds have been prepared by an arc-melting method without further annealing. As-cast samples crystallize in single phase with hexagonal MgZn2-type structure, and exhibit a first-order transition from ferromagnetic to antiferromagnetic state for x<0.3. With the increase of Zr content (x<0.3), the transition shifts towards lower temperature with sharper magnetization change and enhanced magnetization. Field-induced metamagnetic transition from antiferromagnetic to ferromagnetic state was observed around the transition, giving rise to the large magnetocaloric effect. The adjustable transition temperature and large magnetocaloric effect make the as-cast Hf0.83−xZrxTa0.17Fe2 compounds potential candidate as magnetic refrigerants.