Two Evidences for Enlargement of Remnant Polarization in Vanadium-Doped Bi₄Ti₃O₁₂

Abstract

The investigations on the ferroelectric and dielectric properties of vanadium-doped Bi₄Ti₃O₁₂ ceramics are presented. V-doping did not affect the basic crystal structure of Bi₄Ti₃O₁₂. However, the degree of the lattice distortion varied with doping, which causes the variation of the internal strain. The sample with the minimized lattice distortion has the largest remnant polarization. The ferroelectric property of Bi₄Ti₃O₁₂ was significantly improved by doping. The 2P _r of Bi₄Ti₃O₁₂ was 16 μC/cm², and it reaches a maximum value of 26 μC/cm² when the vanadium content is 0.03. There were two relaxation peaks (P₁, P₂) in the dielectric loss (D) curves. The activation of the P₁ peak for Bi₄Ti₃O₁₂ ceramics was 0.66 eV. The P₁ and P₂ peaks relating to oxygen vacancies reduced with V doping, which give a clue that V-doping restrains the oxygen vacancy concentration. The enlargement of 2P _r in V-doped Bi₄Ti₃O₁₂ is associated with the internal strain and the restraint of oxygen vacancies.

ACKNOWLEDGEMENT

The authors acknowledge the financial support by the National Natural Science Foundation of China (Grant No. 10274066).