Giant reversible magnetocaloric effect in a multiferroic GdFeO3 single crystal

Abstract

The magnetocaloric properties of single crystalline ${\mathrm{GdFeO}}_{3}$ have been investigated in the temperature range 2--36 K by magnetization and heat-capacity measurements. Remarkably large and reversible magnetic entropy change, $\mathrm{\ensuremath{\Delta}}{S}_{\mathrm{m}}=\ensuremath{-}52.5$ J/kg K, has been observed for a field change of 0--9 T. The adiabatic temperature change, $\mathrm{\ensuremath{\Delta}}{T}_{\mathrm{ad}}$, is also found to be very large, 22 K, slightly above the antiferromagnetic ordering temperature (${T}_{N}^{\text{Gd}}=2.5$ K) of the ${\mathrm{Gd}}^{3+}$ moment, for a field change of 0--8 T. These magnetocaloric parameters remain large down to the lowest temperature measured and are significantly larger than that reported for the other members of rare-earth ($R$) orthoferrites ($R{\mathrm{FeO}}_{3}$) and several potential magnetic refrigerants in the same temperature range. Both $\mathrm{\ensuremath{\Delta}}{S}_{\mathrm{m}}$ and $\mathrm{\ensuremath{\Delta}}{T}_{\mathrm{ad}}$ are also quite large for a small field change. The large values of magnetocaloric parameters suggest that ${\mathrm{GdFeO}}_{3}$ could be considered as a potential refrigerant in low-temperature magnetic refrigeration technology, such as liquefaction of hydrogen in the fuel industry. Moreover, ${\mathrm{GdFeO}}_{3}$ has very low electrical conductivity and exhibits no thermal and field hysteresis in magnetization, fulfilling the necessary conditions for a good magnetic refrigerant.