Magnetic Properties of Several Metasilicates and Metagermanates with Pyroxene Structure

Manganese metasilicate and manganese, ferrous and cobalt metager-manates with pyroxene structure were prepared by usual ceramic techniques. Ferrous and cobalt metasilicates were synthesized under high pressure. The magnetic susceptibilities of the eight pyroxenes were measured in the temperature range from 4.2 to 300°K. All of these pyroxenes are antiferromagnetic at low temperatures. The Néel temperatures of MnSiO 3 , MnGeO 3 , CoSiO 3 , and CoGeO 3 are respectively 7°K, 10°K, 50°K and 41°K. The susceptibility-temperature curves for FeSiO 3 and FeGeO 3 show two peaks. They are discussed on the basis of a simple molecular field approximation.