Magnetic Properties of Several Orthosilicates with Olivine Structure

Abstract

The magnetic susceptibilities of Mn-, Fe-, Co- and Ni-orthosilicates were measured between 4.2°K and room temperature. All of these silicates are antiferromagnetic at low temperatures. The susceptibility-temperature curve for Mn-orthosilicate begins to deviate from the Curie-Weiss law at 75°K, and it has a broad peak at 15°K. In Fe-orthosilicate, it has two peaks at 62°K and 23°K. The antiferromagnetic behaviors of these two silicates are rather unusual. They are discussed using a simple Weiss-field approximation. Co- and Ni-orthosilicates behave as ordinary antiferromagnetics. Their Néel temperatures are 47°K and 33°K, respectively.