Structure and multiferroic properties of Sr substituted Bi0.89−xSm0.11SrxFe0.94(Mn0.04Cr0.02)O3 thin films

Sr2+ substituted Bi0.89−xSm0.11SrxFe0.94(Mn0.04Cr0.02)O3 (BSSrFMC, x=0.00 0.02, 0.04 and 0.06) thin films were prepared on FTO/glass (SnO2:F) substrates by using a sol-gel method. The effects of Sr2+ substitution on the structure, leakage current, dielectric, ferroelectric and magnetic properties of BSSrFMC thin films have been investigated. X-ray diffraction (XRD), Rietveld refinement of XRD patterns and Raman spectroscopy results indicated two space groups (P4 and P422) to coexist in the tetragonal BSSrFMC thin film when x=0.04. Meanwhile, the lattice constant a was increased compared with that of the non-doped BSFMC thin film, which may result in an expanded unit cell. Highly enhanced multiferroic properties were observed in the BSSrFMC thin film with x=0.04, i.e., large remanent polarization (2Pr=173.43 μC/cm2), and large saturated magnetization (Ms=2.3 emu/cm3). Furthermore, a giant dielectric constant of 290 was observed in the BSSrxFMC (x=0.04) thin film at 1 kHz.