Magnetoresistance on direct and alternating current in manganese selenide substituted with thulium

The scale of electrical inhomogeneity in manganese selenide substituted with thulium for magnetoresistance at direct and alternating current is investigated using I–V characteristics measured without a field and in a magnetic field in the paramagnetic phase. A correlation was found between the nonlinearity of the I–V characteristic and the magnetoresistance at direct current. A decrease in resistance in a magnetic field on alternating current was discovered with increasing concentration of thulium ions. The difference in magnetoresistance for direct and alternating current is explained by taking into account the contribution of dielectric constant in the magnetodielectric resonance model.