Structural and physical properties of Ti-doped BiFeO3 nanoceramics

Enhanced ferroelectricity and magnetization have been observed in Ti-doped BiFeO3 nanoceramics prepared using spark plasma sintering processes. X-ray diffraction and FESEM investigations suggested the formation of a pure rhombohedral phase BiFe(0.9)sTi(0.05)O(3) (BFTO) ceramics with an average grain size less than 100 nm. Low dielectric loss and conductivity were attributed to low concentration of Fe-2 (Fe-3/Fe2+ is 2.8) measured by Xray photoelectron spectroscopy. The remanent polarization test identified the intrinsic ferroelectricity in BFTO nanoceramics. The piezo-response force microscopy measurements showed nano-scaled ferroelectric domains in BFTO nanoceramics. High remanent magnetization (M-r = 0.1 emu/g) was attributed to the collapse of the cycloidal spin structure for the substitution of Fe3+ with Ti4+ and the existence of nanoscaled grains less than the period (62 nm) of the spin cycloid.