Phase study of Chevrel compounds of PbxMo6Se8−y and CdxMo6Se8−y

Phase relations on the ternary system of Pb–Mo–Se at 1273 K were studied in the vicinity of Chevrel phase, PbMo6Se8. The PbMo6Se8 phase was found to be stabilized in the composition ranges, 0.9≦x≦1.1 and 7.50≦(8−y)≦7.65 for the formula PbxMo6Se8−y. Superconducting transition temperature of this phase was observed at Tonset=5.0±0.1 K. The tentative stability region of the CdMo6Se8 phase was observed to lie in the range 0.95≦x≦1.10 for CdxMo6Se7.5. Both phases showed the positive Seebeck coefficients of +10–+20 μV/K.