Low-temperature heat capacity of CdGa2S4

Abstract

Intensive studies on the physicochemical properties of A I I B F C y -t y p e compounds have revealed their promising nature with respect t o semiconductor engineering (electrophotography, non-linear optics, switching and memory devices), and the diversity of crystal structures and the investigation of their effect on the lattice dynamics make the A"BFC1' compounds interesting from a purely physical standpoint, too.Other reports /1 t o 3/ deal with investigations of the heat capacity of CdIn2S4 and CdGaInS4 in the temperature range from 5 t o 300 K and that of CdGa2S4 i n the range from 1 5 to 300 K.of CdG?S4 in the temperature range from 5 t o 80 K. The heat capacity was measured by the adiabatic calorimetric method with an automatic temperature control /4/. The experimental e r r o r amounted t o 0.3 to 0.2% in the temperature range from 1 0 t o 80 K and maximum 5% below 1 0 K.The temperature dependence of the heat capacity of CdGa2S4 is shown in Fig. 1. Below * 60 K the data of /3/ differ from ours, whereas above 60 K they are in full e r e e m e n t with the data obtained by us. In /3/ the adiabatization of the experimental conditions was carried out manually, which led to a long temperature travel of the calorimeter and t o the protraction of the thermal equilibrium time, and hence to larger e r r o r s while measuring the heat capacity of a material and calibrating the empty calorimeter. It is mainly with this fact that the above discrepancy is likely t o be associated.The present report gives results obtained while measuring the heat capacity Below x 7 K the heat capacity of CdGaZS4 obeys the cubic law: C v 5 =! ?. x 4 R ( e .with the Debye temperature aD = (1 7l 2 1)K. 1 ) prospekt Narimanova 33, 370143 Baku, USSR.