Metal–semiconductor transition in Sm_<i>x</i>Mn_1−<i>x</i>S solid solutions

Abstract

Abstract The electrical resistivity of the Sm x Mn 1− x S (0.15 ≤ x ≤ 0.25) solid solutions in the temperature range of 80–300 K was measured. Minimum and maximum in the temperature dependence of the resistivity were found, respectively, at T = 220 K for x = 0.15 and at T = 100 K for x = 0.2 compounds. This behavior is explained from the result of the mobility‐edge movement, the disorder being due to elastic deformation and spin density fluctuations with short‐range order. Metal–semiconductor phase transition versus concentration at x c = 0.25 is observed. Resistivity is described by scattering electrons with acoustic phonon mode and with localized manganese spin. From the thermal expansion coefficient the compression of the lattice below the Néel temperature for Sm 0.2 Mn 0.8 S is found.