Transport and thermoelectric properties of Cr1−xMnxSb2 at low temperatures

The effect of Mn substitution on transport and thermoelectric properties of Cr1−xMnxSb2 (x = 0, 0.01, 0.03, 0.05) have been investigated at the temperatures from 7 K to 313 K. The results show that similar to CrSb2 all the doped samples are semiconducting. However, electrical resistivity of Cr1−xMnxSb2 is found to decrease greatly with increasing doping content of Mn. Besides, Mn substitution leads to suppression of the plateau appearing in the plot of resistivity vs. temperature for CrSb2 and makes the resistivity anomaly originating from antiferromagnetic transition shift to higher temperatures. Moreover, corresponding to the plateau a large peak of thermopower (−431 μV K−1) was observed at ∼60 K, which was also found to be suppressed by Mn doping. In addition, lattice thermal conductivity of Cr1−xMnxSb2 was found to decrease substantially with increasing Mn content, though Mn doping also results in slow reduction in absolute value of thermopower at the temperatures T > ∼200 K. As a result, at T > ∼260 K the figure of merit ZT of heavily doped sample Cr1−xMnxSb2 (x = 0.03 and 0.05) was improved. Specifically, at 313 K ZT value of Cr0.95Mn0.05Sb2 is ∼14% larger than that of CrSb2, indicating that thermoelectric properties of CrSb2 can be improved by proper substitution of Mn for Cr.