Ram S. Katiyar

Studies of Bi 4−x Gd x Ti 3 O 12 Bifunctional Material

Gadolinium-substituted Bi 4 Ti 3 O 12 (i.e. Bi 4−x Gd x Ti 3 O 12 ) were synthesized by sol-gel process for different compositions, and thin films were deposited on Pt (Pt/TiO 2 /SiO 2 /Si) substrate by spin coating. Post annealed films at 700° C were investigated for their structural properties using x-ray diffraction and Raman spectroscopy indicating solid solution for compositions: x = 0.00, 0.46, 0.56, and 0.85 where Bi ion is replaced by Gd-ion. Sol-gel derived Pt/Bi 4−x Gd x Ti 3 O 12 film/Pt capacitor structure was tested for dielectric, ferroelectric, and leakage current responses. Films showed ferroelectricity with polarization, P r = 22 µC/cm 2 for composition: x = 0.46. Magnetic response of the powder sample for composition: x = 0.85 was tested using SQUID, which showed superparamagnetic at room temperature and magnetic at 5 K with magnetic coercivity (Hc) = 29 Oe and very small remanance (σ r ) = 5.4 × 10 −4 emu/g.