Heat capacity and magnetic phase transitions of rare-earth orthoferrite HoFeO3 Original Research Article

Heat capacity of two rare-earth orthoferrites HoFeO3 and LuFeO3 were measured between 1.8 and 200 K. A distinctly large and two small heat capacity anomalies were detected for HoFeO3 under zero magnetic field around 3.3, 53 and 58 K, respectively. The low-temperature anomaly with a peak at 3.3 K is due to the ordering of Ho3+ ions and the estimated magnetic entropy for this transition was favorably compared with the expected (R ln 2). Application of magnetic field significantly affects the positions and the magnitudes of the anomaly at 3.3 K. Energies of low-lying levels of the lowest J-term of Ho3+ ion were roughly estimated through analysis of the Schottky heat capacity.