Lattice Thermal Expansion in CuGaT 2 and CuInTe 2 Compounds over the Temperature Range 80 to 650 K from X‐ray Diffracion Data

The lattice parameters a and c as well as the thermal expansion coefficients α⟂ and α∥ in the two principal direction for CuGaTe 2 and CuInTe 2 chalcopyrite‐type compounds have been determined as a function of temperature in the range from 80 to 650 K by the X‐ray diffraction method. It is found for both the compounds the coefficient of expansion along the α axis (α⟂) is larger than that along the c axis (α∥) over the whole investigated tem‐perature range. When comparing the results for a series of the CuB III C   VI 2compounds (BGa, In; CS, Se, Te) it is shown that the thermal expansion anisotropy increases strongly when the Ga atom replaces the In atom while it changes a little when the Te atom replaces the Se atom or the S atom.