It is known that the zircon-type orthovanadates $\mathrm{RV}{\mathrm{O}}_4$ show promise in many different applications as catalysts and optical materials. In this work, we demonstrate that the $\mathrm{TbV}{\mathrm{O}}_4$ compound can be also used as magnetic refrigerant in efficient and ecofriendly cryocoolers due to its strong magnetocaloric effect at low-temperature regime. The application of a relatively low magnetic field of 2 T along the easy magnetization axis ($a$) gives rise to a maximum entropy change of about 20 J/kg K at 4 K. More interestingly, under sufficiently high magnetic fields, the isothermal entropy change $-\mathrm{\Delta }{S}_{\mathrm{T}}$ remains approximately constant over a wide temperature range which is highly appreciated from a practical point of view. In the magnetic field change of 7 T, $-\mathrm{\Delta }{S}_{\mathrm{T}}$ that reaches roughly 22 J/kg K remains practically unchanged between 0 and 34 K leading to an outstanding refrigerant capacity of about 823 J/kg. On the other hand, the lowering of crystallographic symmetry from the tetragonal to the orthorhombic structure occurring close to 33 K as confirmed by Raman scattering data results in a strong magnetic anisotropy. Accordingly, strong thermal effects can be also obtained simply by spinning the $\mathrm{TbV}{\mathrm{O}}_4$ single crystals between their hard and easy orientations in constant magnetic fields instead of the standard magnetization-demagnetization process. Such rotating magnetocaloric effects would open the way for the implementation of $\mathrm{TbV}{\mathrm{O}}_4$ in a new generation of compact and simplified magnetic refrigerators that can be dedicated to the liquefaction of hydrogen and helium.

• Received 27 July 2020
• Revised 22 October 2020
• Accepted 26 October 2020

DOI:https://doi.org/10.1103/PhysRevMaterials.4.114411