P. Peshev, G. Bliznakov, A. Toshev
Apr 1, 1968
Citations
0
Influential Citations
6
Citations
Journal
Journal of The Less Common Metals
Abstract
Abstract The optimum conditions for the preparation of stoichiometric gadolinium sesquisulphide and gadolinium monosulphide according to the reactions Gd 2 O 3 +3 H 2 S = Gd 2 S 3 +3 H 2 O (1) and Gd 2 O 3 +2 Gd 2 S 3 + 3 C = 6 GdS +3 CO (2) have been investigated. It has been established that stoichiometric Gd 2 S 3 is obtained at temperatures above 750 °C. Gadolinium monosulphide was prepared by carrying out reaction (2) in vacuo in two stages : i.e. , the stoichiometric mixture of the three components was heat-treated at 1600 °C for 2–3 h, ground and pressed into pellets, then heat-treatment of the pellets was carried out at 1700 °C for 2 h. The magnetic susceptibilities of Gd 2 S 3 and GdS have been measured and the effective magnetic moments have been determined. The latter are close to the magnetic moment of the Gd 3+ ion which indicates the prevalence of ionic bonds in both sulphides. The dependence on temperature of the work function, ϑ, for cathodes of Gd 2 S 3 and GdS has been investigated. The conductivities of both sulphides have been determined theoretically; Gd 2 S 3 is deduced to possess a semiconducting, and GdS a metal, conductivity.