Multiferroics: Wide-bandgap semiconductors with challenging applications

Multiferroics, i.e. functional materials that combine ferromagnetic (FM) and ferroelectric (FE) ordering within one and the same element are very rare at room temperature (RT). Nevertheless, in the view of modern oxide electronics, multiferroics offer a superb set of novel functionality down to the unit cell level. To profit from these materials we witness a very active and ongoing research in synthesizing such materials or material combinations. Besides single phase RT bismuth ferrite (BFO) thin films, hetero-structures are widely en vogue, however facing severe preparational challenges; here either laterally or vertically grown composite materials deliver an overall ensemble response that has the desired multifunctional behavior. Moreover, individual oxide material layers allow also for n- and p-doping similar to standard semiconductor technology; this considerably broadens their applicability and functionality. I will sketch a series of such very intriguing and challenging applications for both the electronic and optical integration.