Room temperature multiferroic behavior of Cr-doped ZnO films

Single-phase 9 at. % Cr-doped ZnO filmhas been prepared on Pt(III)/Ti/SiO(2)/Si(100) substrates by reactive sputtering method. The film is found to present ferroelectric and ferromagnetic behaviors simultaneously at room temperature, and it undergoes transitions to paraelectric and paramagnetic phases at similar to 368-373 and similar to 495 K, respectively. It is considered that the local electric dipoles induced by the distortions of CrO(4) tetrahedra should be responsible for the ferroelectricity. On the other hand, the ferTomagnetic ordering could be explained by the interaction of the localized spins with statically occupied polaron states. The multiferroic behavior adds a dimension to the multifunction of ZnO. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.2978221]