Research on electrical properties of manganese sulphides doped by thulium and ytterbium ions

Materials exhibiting connection between electrical and magnetic properties are attractive for possible use as an element base in microelectronics, spintronics, and sensor devices. Compounds with mixed valence exhibit a number of metal-insulator phase transitions, magnetic phase transitions, including changes in magnetic properties without changing magnetic symmetry. Promising materials for studying these effects are cation-substituted Mn1−xRexS compounds (Re = 4f elements) synthesized on the basis of the antiferromagnetic semiconductor of manganese monosulfide. The latter is of practical importance in the development of new materials for temperature sensors, widely used in the metallurgical industry. The structural and electrical properties of compounds with mixed valences TmXMn1-ХS (0 ≤ X ≤ 0.15) and TmXMn1-ХS (0 ≤ X ≤ 0.25) were studied in the temperature range 80–1100K. The regions of existence of solid solutions of TmXMn1-XS sulfides with an fcc (face-centered cubic) lattice of the NaCl type were determined. It was found that conductivity decreases upon the substitution of manganese cations with thulium ions and the lattice constant increases more sharply in comparison with Vegard’s law. When ytterbium ions are substituted, the conductivity increases with increasing concentration and the temperature dependence has the form typical of semiconductors.