Structure of BaTi(subscript 1−x)Fe(subscript x)O(subscript 3-δ) Multiferroics Using X-ray Analysis

N. V. Dang；Ha M. Nguyen；Pei-Yu Chuang；T. D. Thanh；V. D. Lam；Chih-Hao Lee；L. V. Hong

Chinese Journal of Physics

50卷2期（2012 / 04 / 01）

262 - 270

英文

BaTiO(subscript 3-δ) (BTO) and BaTi0.88Fe0.12O(subscript 3-δ) (BTFO) polycrystalline samples were investigated to understand the role that Fe dopant and oxygen vacancy play on their various properties. Their structures were examined using X-ray diffraction and X-ray absorption spectroscopy. Their optical and conduction properties were also characterized at room temperature. Our results show that BTO is a tetragonal-phase ferroelectric material with a wide band gap E(subscript g) ≈ 3.51 eV while BTFO is a hexagonal-phase multiferroic material with smaller band gap E(subscript g) ≈ 3.40 eV. Fe doping ions, which exist in both Fe(superscript 3+) and Fe(superscript 4+) forms, give rise to positively-charged oxygen vacancies to create donor impurity levels in the forbidden band. The UV-VIS absorption spectrum of BTFO exhibits a broadening in the visible region. The red shift is observed in both the absorption and photoluminescence spectra relative to those of BTO. The leakage current is larger in BTFO than in BTO.