Investigation of the transport properties of cation-substituted solid solutions Yb$_x$Mn$_{1-x}$S

The electrical properties and thermopower of solid solutions Yb$_x$Mn$_{1-x}$S with substitution concentrations 0 $<x\le$ 0.2 have been studied in the temperature range of 77–1050 K. It has been found that the electrical conductivity has a semiconducting character, and the thermopower changes its sign from positive to negative as the substitution concentration in Yb$_x$Mn$_{1-x}$S increases. It has been established that the activation energy decreases with increasing ytterbium concentration. The model of impurity donor 4$f$ states satisfactorily agrees with the data on the electrical resistivity and the thermopower.