HEXAFERRITES - SINGLE PHASE MAGNETO-ELECTRIC MULTIFERROICS

Multiferroic materials are an exceptional class of magnetic materials where long-range magnetic and ferroelectric orders coexist, thus provoking the researchers’ interest from both basic and practical points of view. The magneto-electric multiferroics are materials that combine coupled electric and magnetic dipoles. Recently, research has focused on the occurrence of the magnetoelectric effect in some hexagonal ferrite types and the possibility of their use as single-phase multiferroic and magnetoelectric materials. For many years, various hexaferrites have been intensively studied as materials for permanent magnets, high-density recording media, microwave devices, biomedical applications, etc. The magnetic structure and especially the specific magnetic spin arrangement under certain conditions proved to be key factors for the realization of magneto-electric phases in hexaferrites. Here some recent advances in our studies of the magnetic phase transitions in the Y-type hexaferrites are overviewed. In particular, the influence of the replacement of non-magnetic Me2+ cations with magnetic cations and of magnetic Fe3+ cations with non-magnetic ones on the magnetic properties and occurring magnetic phase transitions in Y-type hexaferrites are exemplified with Ba0.5Sr1.5Zn2Fe12O22.