Temperature variation of lattice parameters and thermal expansion coefficients of the compound ZnGa2Se4

X-ray powder diffraction measurements on ZnGa2Se4, a II-III2-VI4 semiconductor compound, were made in the temperature range between 300 K and 700 K, a region in which this material has a defect tetragonal structure. From the analysis of the X-ray diffraction lines, accurate lattice parameter values were determined as a function of temperature. These results allowed the evaluation of the thermal expansion coefficients of the corresponding parameters. The observed increase, with the temperature, of the tetragonal deformation delta(= 2 - c/a) as well as of the crystal anisotropy A(alpha)(= alpha(a) - alpha(c), with alpha(a) > alpha(c)) was then explained by using the relations proposed by Abrahams and Bernstein. (C) 1997 Elsevier Science Ltd.