3d-4f spin interaction induced giant magnetocaloric effect in zircon-type DyCrO4 and HoCrO4 compounds

TL;DR

This study investigates the magnetic and magnetocaloric properties of DyCrO4 and HoCrO4 compounds, revealing large entropy changes and temperature shifts suitable for magnetic refrigeration, driven by 3d-4f spin interactions.

Contribution

It demonstrates that zircon-type DyCrO4 and HoCrO4 exhibit significant magnetocaloric effects due to 3d-4f spin interactions, highlighting their potential as magnetic refrigerants.

Findings

Maximum magnetic entropy change up to 31 J/kg·K at 8 T.

Adiabatic temperature change up to 12 K for HoCrO4.

Refrigerant capacity exceeding 600 J/kg.

Abstract

We have investigated the influence of 3d-4f spin interaction on magnetic and magnetocaloric properties of DyCrO$_4$ and HoCrO$_4$ compounds by magnetization and heat capacity measurements. Both the compounds exhibit complicated magnetic properties and huge magnetic entropy change around the ferromagnetic transition due to the strong competition between ferromagnetic and antiferromagnetic superexchange interactions. For a field change of 8 T, the maximum values of magnetic entropy change ($\Delta S_{M}^{max}$), adiabatic temperature change ($\Delta T_{ad}$), and refrigerant capacity (RC) reach 29 J kg$^{-1}$ K$^{-1}$, 8 K, and 583 J kg$^{-1}$, respectively for DyCrO$_4$ whereas the corresponding values for HoCrO$_4$ are 31 J kg$^{-1}$ K$^{-1}$, 12 K, and 622 J kg$^{-1}$. $\Delta S_{M}^{max}$, $\Delta T_{ad}$, and RC are also quite large for a moderate field change. The large values of magnetocaloric parameters suggest that the zircon-type DyCrO$_4$ and HoCrO$_4$ could be the potential magnetic refrigerant materials for liquefaction of hydrogen.