Multiferroic properties of Dy modified BiFeO_3 thin films in comparison with Tb modified BiFeO_3 thin films

摘要

Coexistence of ferroelectric and ferromagnetic order parameters was observed at room temperature in Bi_(0.6)Dy_(0.3)La_(0.1)FeO_3 thin films grown on Pt/TiO_2/SiO_2/Si substrates using a pulsed laser deposition technique similar to that for Bi_(0.6)Tb_(0.3)La_(0.1)FeO_3. The coexistence of ferroelectric and magnetic domains in specific spatial area of the thin film was also confirmed by scanning probe imaging. As expected, the magnetization values obtained for Bi_(0.6)Dy_(0.3)La_(0.1)FeO_3 bulk and thin films were higher than those of Bi_(0.6)Tb_(0.3)La_(0.1)FeO_3 bulk and polycrystalline thin films because the magnetic moment of Dy is higher than that of Tb. However, preferentially oriented thin films of Bi_(0.6)Tb_(0.3)La_(0.1)FeO_3 exhibit much higher magnetization values. It is speculated that structural alignment caused by stress developed during deposition of these films could be responsible for enhancement in magnetization.