Magnetocaloric properties of the hexagonal HoMnO₃ single crystal revisited

Magnetic and magnetocaloric properties of the hexagonal HoMnO₃ single crystal have been revisited. It was found that the magnetocaloric effect shown by HoMnO₃ strongly depends on the crystal orientation in respect to the applied magnetic field. Consequently, a large thermal effect can be induced by spinning the single crystal HoMnO₃ around the a (or b) axis in a constant magnetic field instead of the conventional magnetization–demagnetization process. Under 7 T, the maximum rotating entropy change was evaluated to be about 8 J/kg K. The associated adiabatic temperature change reaches a value of about 5 K. These values are comparable to those of the other oxides exhibiting a large rotating magnetocaloric effect. The presence of both conventional and rotating thermal effects makes the hexagonal HoMnO₃ more interesting from a practical point of view.