Multiferroic Properties In Complex Oxides

Often papers dealing with multiferroics (MFs) begin by defining the complex group of materials they deal with. This compelling need highlights the complexity of the issue and the importance of a common language, in consideration of the various communities involved. Our article follows a bottom-up approach by introducing the playground of electrons in matter, their susceptibilities and possible spontaneous orders in simple cases. Then, multiferroic properties are recalled, together with a number of examples. Special attention is focused on the magnetoelectric interaction. The fundamental role of oxides in the field is pointed out in terms of number, importance and perspective offered in the panorama of desired applications. A historical overview accompanies the development of concepts, definitions and discoveries. Current challenges and new perspectives are presented.