SEEBECK COEFFICIENTS OF Mn-Si MATERIALS PREPARED BY SPARK PLASMA SINTERING

MnSi_1.73 and MnSi samples were grown by spark plasma sintering (SPS) from different Si/Mn ratio powders, at different sintering temperatures, and for different sintering times. X-ray diffraction (XRD) measurements showed samples containing MnSi and MnSi_1.73 and Si phases, depending on the initial stoichiometries. Measurements of the Seebeck coefficient revealed p-type conductance for all samples. The Seebeck coefficients of the samples with MnSi pure phase were very low (about 10 μ V/K) and changed little at the temperature range measured. The Seebeck coefficients of the samples with MnSi_1.73, MnSi and Si phases were similar to that of the sample with near-pure MnSi_1.73 phase, which were larger than those of the samples with MnSi_1.73 and MnSi phases, but a little smaller than those of the samples with MnSi_1.73 and Si phases. It seems that, for the samples with the same phases, larger ratio of the strongest intensity peak of MnSi_1.73 to , MnSi_1.73 to or both lead to larger Seebeck coeffiecients.