Synthesis of Layered Compounds AFe_6-xMn_xO₁₁ (A=Ba, Sr) by High-Pressure Technique

Abstract

BaFe_6-xMn_xO₁₁ (x=2.0, 3.0 and 3.5) and SrFe₃Mn₃O₁₁ were prepared by high-pressure method, and their crystal structures and physical properties were investigated. The materials crystallize in R-type hexagonal ferrite structure, in which Fe³⁺ ions mainly occupy B(2) and B(3) sites, while Mn ions mainly occupy B(1) site. The compounds show Collinear Gorter-type ferrimagnetic structure, and saturation magnetization and Curie temperature decrease with increasing x. They also show Arrhenius-type semiconducting behaviors.