Enhancement of the magnetoelectric effect in doped BaTiO3 nanoparticles

Experimentally the polarization P and the magnetization M of BaTiO (BTO) nanoparticles are altered under doping with transition metals as Fe-ions. Using a modified spin model for the magnetic and the ferroelectric part as well as the magnetoelectric coupling we have calculated the dependence of M and P on the Fe-doping content in BTO nanoparticles. The ferroelectric and ferromagnetic phase transition temperatures, and , are likewise shifted due to doping. Owing to surface effects the influence of doping could be stronger compared to the bulk behavior. Whereas M and increase with increasing Fe-ion concentration, P and decrease if the dopant concentration is enhanced.