Table-like magnetocaloric effect and large refrigerant capacity in Ho6−xZrxFeSb2 compounds

Abstract

To developing new magnetic refrigeration materials is very important for the application of magnetic refrigeration technology. For this purpose, samples with rare earth element Ho in Ho6FeSb2 substituted by 4d transition element Zr were prepared, and the crystal structure and magnetic properties of Ho6−xZrxFeSb2 were studied. Density functional theory calculations and synchrotron powder X-ray diffraction data analysis indicate that Zr is not randomly doped but rather preferentially occupies the 3 g site in the Ho6−xZrxFeSb2. Magnetic data show that the substitution of Ho by Zr follows with the reduction of the number of unpaired electron number, which will weaken the magnetic exchange interactions, and further depress the TC. Owing to two magnetic transitions of spin reorientation and paramagnetic-ferromagnetic transition, Ho6−xZrxFeSb2 shows table-like magnetocaloric effect. The Ho6FeSb2 exhibits large maximum magnetic entropy change of 12.23 J/kg K and high refrigeration capacity of 660.42 J/kg under 4 T. Substituting Ho with cheaper Zr reduces cost of the material, as well as provide new ideas for material researchers.