Crystal Phase and High Frequency Characteristics of Manganese Substituted Z-type Hexagonal Ferrites

Abstract

A series of room-temperature ferromagnetic mixed oxides, Ba₃Co₂Mn_xFe_24-xO₄₁, with z-type structure, has been synthesized by high temperature solid-state reaction. Ba₃Co₂Mn_xFe_24-xO₄₁ was made from BaCO₃, CoO, Mn₂O₃ and α-Fe₂O₃. The structure was determined by x-ray diffraction method; single phase with z-type structure was obtained for Ba₃Co₂Mn_xFe_24-xO₄₁(x=0, 1, 2). Frequency dependence of initial permeability of all samples was investigated. The initial permeability of Ba₃Co₂Mn₁Fe₂₃O₄₁ was 13 (at 0.1 MHz), which was highest of all samples. One of the reasons is due to the change of magnetocrystalline anisotropy which caused by Mn ions and Fe ions. The other is decrease of the magnetostriction caused by Jahn-Teller effects which induced by Mn₃₊ ions.