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K145 2-I om-I ) 5 . 6~1 0~ 5 07 1 . I 4.3~1 O2 phys. stat. sol. 24, K145 (1967) Subjeot olassirioation: 8 and 15; 5; 14.3; 22 Institute of Physics, Academy of Sciences o r the Azerbaidzhan SSR, Baku On Some Characteristics of Chromium Selenides BY V.A. IVANOVA, D.SH. BBDINOV, and G.M. ALIEV The lattice constant and electrical conductivity of some chromium selenides are studied in the works (1 to 3), but data on the thermal conductivity and thermoelectric power of the named compounds &we absent in literature. As these data give valuable information about the kinetic processes taking place in materials we have synthesized the compounds CrSe, Cr7Se0, Cr3Se4, and Cr Se electrical and thermal conductivity and thermoelectric power.(1 to 3). The phase composition was determined with the aid of X-rays and microscopical analysis.

Some structural (1) and physical (2) features of InSe make it interesting for heat conductivity investigation. That is why we have studied the heat conductivity of InSe single crystals over the range 100 to 600 K in different crystallographic directions. physica status solidi 28 additional thermal resistance in the direction parallel to the c-axis.

The thermal conductivity λ of amorphous, crystalline, and liquid selenium (purity 99,99999 %) is measured in the temperature range 80 to 525°K which includes the softening (T ≈ 31°C) and melting points. The thermal conductivity of amorphous selenium increases linearly with temperature up to 304°K at which temperature there is a discontinuity involving a sharp increase of about 40%. Admixtures of Cd and Tl change the values of the discontinuity Δλg and temperature Tg. An admixture of Cd shifts the value of Δλg from 0.44 × 10−3 to 0.11 × 10−3 cal/(cm s degree) and increases Tg from 30.7 to 33.5°C. Heat treatment increases λ and changes its temperature profile. Admixtures of Tl remove the discontinuity. The thermal conductivity of selenium during melting undergoes a discontinuity of about 40% which is explained by the increase in the intermolecular distance from 3.46 to 3.74 Å. A photon thermal conductivity, which accounts for up to 30% of the overall thermal conductivity, is found in crystalline selenium at temperatures above about 350°K. The experimentally determined value of λ, its temperature dependence, the values of the softening and melting discontinuities and the photon parts agree well with theory.

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