Magnetically Ordered Ferroelectric Materials

The varieties of compounds and solid solutions in which simultaneous ferroelectric properties and magnetic order have been demonstrated are reviewed and literature references are given. Materials investigated so far have contributed to fundamental understandings of processes in crystals and a variety of techniques and subtle inferences have been required in their investigation. Classification of some substances, notably BiFeOI has aroused controversy requiring many experiments to settle. Theoretical considerations have concentrated on the interactions between electric and magnetic´ fields, and on the type of magnetoelectric effect predicted to be characteristic of MOF. As yet, magnetic moments achieved are insufficient for device application, and frequently high electrical conductivity is a problem. However, the number of substances investigated is large, favorable individual properties exist in many, and the rate of research on such MOF together with new methods of synthesis imply improved properties in the future. From the applications point of view, the scientific field can be classed as emergent. Properties both below and above the Curie point are in some cases approaching those required for microwave application. Probable applications will be as improved or modified materials where ferroelectrics are presently used and in areas in which the interaction between electric and magnetic fields is utilized.