Polycrystalline HoMnO3 (HMO) samples were prepared through the solid-state reaction method to study their magnetic, thermal and magnetocaloric properties. X-ray diffraction studies revealed that the sample crystallized in hexagonal structure with P63cm space group. Low-temperature magnetization measurements showed an anomaly at 4 K, whereas the heat capacity measurements carried out under 0 T, 2 T, 5 T and 9 T fields in the temperature region of 2–150 K exhibited three different transitions at 72 K, 33 K and 5 K. These transitions are attributed to the ordering of Mn3+, spin reorientation of Mn3+ ions and Ho3+ ions, respectively. Magnetic contribution to the total entropy change was also evaluated at different magnetic fields. Magnetocaloric effect (MCE) parameters such as isothermal entropy change of 2 J/kg-K, 9 J/kg-K and 16 J/kg-K were obtained at around 10 K for a magnetic field change of 2T, 5T and 9T, respectively. The adiabatic temperature change (ΔT) values are found to be 0.6 K, 3.5 K and 8.5 K, whereas the relative cooling power (RCP) is found to be 4 J/kg, 120 J/kg and 360 J/kg under 2T, 5T and 9T magnetic field change, respectively.
P. N. Kumar, Singh, D., Patidar, M. Mishra, Jyotirmayee Satapathy, Ganesan, V., Babu, P. D., Srinivas, A., and M. Raja, M., “Magnetic, thermal and magnetocaloric studies of polycrystalline HoMnO3 compound”, Applied Physics A, vol. 125, p. 487, 2019.