Heat-capacity anomaly due to spin reorientation and thermodynamic functions of ErFeO3 and TmFeO3

Heat capacities of orthoferrites, ErFeO3 and TmFeO3, have been measured bel ow room temperature by adiabatic calorimetry. A broad but definite anomaly due to the spin reorientation phenomenon was successfully detected in the e xpected temperature range (ca. 90 K). The results are compared with a vast anomaly reported for YbFeO3. The temperature dependence of the electric qua drupole splitting of the Fe nuclear levels was determined by Mossbauer spec troscopy through the spin reorientation, A heat capacity anomaly centered a t 3.60 K due to the magnetic ordering of Er3+ ions was clearly detected. So me Schottky anomalies were resolved and energy splittings involved were rou ghly estimated. Some thermodynamic functions are derived and tabulated. (C) 2001 Elsevier Science B.V, All rights reserved.