Magnetic and heat-capacity anomalies of La7/8Ca1/8MnO3

The magnetic behavior of the perovskite-like colossal magnetoresistance compounds La1-xCaxMnO3, in the low doping range (x = 1/8), has been studied with AC magnetic susceptibility and heat-capacity measurements from 5 to 340 K. The compound shows three distinct anomalies at 315, 146 and 80 K, and a small broad feature around 35 K. The transition temperature of the 80 K anomaly and the magnetic susceptibility between 80 and 146 K show frequency dependence. The anomaly around 35 K presents hysteresis. The anomalous heat capacity and entropy have been obtained from the measurements. Our findings reveal a complex phase diagram of La1-xCaxMnO3 for x 0.2. (C) 1999 Elsevier Science B.V. All rights reserved.