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".
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