Defect Samarium Ions and Electromotive-Force Generation in SmS

V. V. Kaminskiy, A. V. Golubkov, and L. N. Vasil'ev

Ioffe Physicotechnical Institute, Russian Academy of Sciences, ul. Politekhnicheskaya 26, St. Petersburg, 194021 Russia

Received November 29, 2001

Abstract-A model explaining electromotive-force generation in SmS under heating in the absence of external temperature gradients is considered. An analysis of data on the density of SmS single crystals with composi­tional deviations from stoichiometry in the homogeneity range suggests that excess samarium ions occupy vacancies on the sulfur sublattice. Possible concentrations of defect samarium ions are determined (up to 2.8 ´ 10²¹ cm^-3). The temperature interval within which electromotive force appears in various SmS samples (440- 640 K) and the critical conduction-electron concentrations at which the generation sets in [(6.0-8.5) ´ 10¹⁹ cm^-3] are calculated. An expression permitting estimation of the magnitude of the observed effect is pro­posed. © 2002 MAIK "Nauka/Interperiodica".

download the full version