The Low‐Temperature Thermoelectric Power and Thermal Conductivity of GeTe and of Some GeTe‐MnTe Alloys

A method of preparation has been developed which allows the growth of large homogeneous single phase ingots of such alloy systems as GeTe‐MnTe, GeTe‐SnTe, etc. … We have measured the thermoelectric power and the thermal conductivity of both GeTe and two alloys of the system Ge1−xMnxTe, in the temperature interval 2.5 to 110 °K, the thermoelectric measurements being extended to 350 °K. Using conventional transport theory both the lattice and the electronic contributions to these effects have been obtained. The temperature dependence of these properties was found to be of similar shape for the GeTe‐MnTe samples as for the pure GeTe, even below the known magnetic transition temperature of these samples. To explain the behaviour of the diffusion term of the thermoelectric power, however, the influence of the incomplete Mn d‐band on the electronic properties of the system must be invoked. The lattice thermoelectric power has the same temperature dependence as the phonon‐drag term in metals. From the analysis of both this component and the lattice thermal conductivity, some informations on the predominant phonon scattering mechanisms have been obtained.