Electrical and thermoelectric measurements on the liquid In-In₂S₃ partial system

Abstract

Measurements of electrical resistivity and thermoelectric power have been made over wide ranges of composition and temperature for the liquid partial system In-In₂S₃. The measurements suggest that the system shows ‘semiconducting’ behaviour between the compositions 43 and 60 at. % S, and ‘metallic’ behaviour between the compositions 100 and 94 at. % In. The resistivity (ρ) is typically of the order of 5 × 10⁻³ Ω cm (43 at. % S)−0·3 Ω cm (60 at. % S), at 1150°K, for the ‘semiconducting’ region. The ln ρ^−1/T plots are good straight lines and the calculated activation energies show some dependence on composition. For the ‘metallic’ region ρ is typically of the order of 10⁻⁵ Ω cm and the ρ^−T plots show a small positive temperature coefficient. The thermoelectric power is negative in the ‘semiconducting’ region with values of the order of −110 μ v/°C (60 at. % S) to −30 μv/°C (43 at. % S). The results are discussed in terms of a short-range-order model and a cluster model for the melts.