57Fe Mossbauer Spectroscopy Study of LaFe_(1-x)Co_xO_3 (x = 0 and 0.5) Formed by Mechanical Milling

摘要

Perovskite-related phases of the type LaFe1-xCoxO3 (x = 0 and 0.5) have been syn-thesised by milling techniques. The materials are of smaller particle size and more susceptible to reduction in a flowing hydrogen/nitrogen gas mixture than their counterparts made by conventional solid state calcination methods. The presence of cobalt enhances the reducibility of iron in the perovskite-related structure and, in contrast to LaFeO3 where the oxide structure is at least partially retained even after treatment in the reducing atmosphere at 1150°C, treatment of LaFe0.5Co0.5O3 in a reducing atmosphere leads to reduction of both Fe3+ and Co3+, their segregation from the oxide matrix, and the formation of an iron-cobalt alloy.