Effects of the Co-Presence of Conflicting Magnetic Anisotropy in Ba Ferrite Particles

Abstract

In Ba ferrite particles magnetocrystalline and shape anisotropies are contemporarily present and conflicting. The strength and evolution of the two anisotropies are studied, through the dependence of the anisotropy constants on temperature. While in pure Ba ferrite particles the anisotropy is uniaxial at all temperatures, since the magnetocrystalline anisotropy clearly prevails on shape anisotropy, in particles modified for employment in recording media the two anisotropies are comparable and at low temperatures the shape anisotropy result stronger than the crystalline anisotropy. Besides the irregular shape of the particles introduces further preferred directions for the magnetization. The Co/Ti-doped particles show a multiple axes anisotropy. The macroscopic magnetic properties are found in relationship with the evolution of the anisotropy. Also the influence that the presence of such multiple anisotropy has on the magnetization switching and on the thermal stability of the magnetization of the Ba ferrite particles is analyzed.