Coercivity enhancement of hexagonal ferrites

Abstract

Hexagonal ferrites have been widely used as permanent magnets since their discovery in the 1950s. In spite of their relatively modest magnetic properties, ferrite magnets still show the best performance-to-cost ratio and different investigators are trying to improve their magnetic capabilities by using different synthesis methods and compositions. Different scientific investigations and techniques (Mössbauer spectrometry, X-ray diffraction, and magnetic measurements) have allowed to optimize the permanent magnet properties of rare earth substituted hexagonal ferrite magnets such as La-Co and Nd-Co Sr and Ba ferrites. However, the solubility of rare earth ions in M-type hexaferrite is very low and their introduction leads to the formation of secondary phases, which must be avoided in order to obtain permanent magnets with optimal properties. © (2013) Trans Tech Publications, Switzerland.