Multiferroic properties of Co and Nd co-substituted Bi5Ti3FeO15 thin films

Co and Nd co-substituted Bi5Ti3FeO15 thin films were prepared on Pt/Ti/SiO2/Si substrates via metal organic decomposition method. The structural and multiferroic properties of the films were investigated. It was found that Co ions enter into the lattice and occupy the Fe site. The Bi4.15Nd0.85Ti3Fe0.5Co0.5O15 films simultaneously exhibit ferroelectric and ferromagnetic properties at room temperature, and its 2Pr and 2Mr are 38 μC/cm2 and 3 kA/m, respectively. Moreover, substitutions create local ferromagnetic order and antiferromagnetic order depending on whether the local bonding is FeOCo or FeOFe/CoOCo, respectively. The competing interaction of the ferromagnetic and antiferromagnetic phases results in an interesting magnetic behavior of the films.

► Co occupies the Fe site in Co-doped Bi4.15Nd0.85Ti3FeO15 (BNTF) film.
► Co doping enhances the ferromagnetism of BNTF due to local FeOCo interaction.
► 50% Co-doped BNTF film possesses room temperature ferroelectricity and ferromagnetism.