Ferroelectricity from iron valence ordering in rare earth ferrites?

Abstract

AbstractThe possibility of multiferroicity arising from charge ordering in LuFe2O4 and structurally related rare earth ferrites is reviewed. Recent experimental work on macroscopic indications of ferroelectricity and microscopic determination of coupled spin and charge order indicates that this scenario does not hold. Understanding the origin of the experimentally observed charge and spin order will require further theoretical work. Other aspects of recent research in these materials, such as geometrical frustration effects, possible electric‐field‐induced transitions, or orbital order are also briefly treated.magnified imageBilayer subunit in R Fe2O4 compounds with proposed charge order rendering it polar.(© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)