Magnetic properties and 151Eu Mossbauer effects of mixed valence europium copper sulfide, EU2CuS3

Ternary europium copper sulfide Eu2CuS3 have been investigated by X-ray diffraction, Eu-151 Mossbauer spectroscopy, magnetic susceptibility, magnetization, and specific heat measurements. In this compound, Eu2+ and Eu3+ ions occupy two crystallographically independent sites. The Eu-151 Mossbauer spectra indicate that the Eu2+ and Eu3+ ions exist in the molar ratio of 1: 1, and the Debye temperatures of Eu2+ and Eu3+ are 180 and 220 K, respectively. In its magnetic susceptibility, the divergence between the zero-field cooled and field cooled susceptibilities appears below 3.4 K. The specific heat has a lambda-type anomaly at the same temperature. From the field dependence of magnetization at 1.8 K, the E U ion was found to be in the ferromagnetic state with the saturation magnetization M-S = 6.7 mu(B). (C) 2004 Elsevier Inc. All rights reserved.