Galvanomagnetic properties of polycrystalline manganese selenide Gd$_{0.2}$Mn$_{0.8}$Se

The electrical and galvanomagnetic properties of the Gd$_{0.2}$Mn$_{0.8}$Se solid solutions are investigated in zero magnetic field and in a field of 13 kOe in the temperature range of 80–400 K. The negative magnetoresistance below room temperature and hysteresis of the I–V characteristics are found. The change in the magnetoresistance sign and thermopower with increasing temperature is established. The carrier type is determined from the Hall constant; the difference between the thermopower and Hall coefficient signs at high temperatures is established. The experimental data are explained using the model of orbital ordering and spin-orbit interaction.