Dielectric and ferroelectric properties of intergrowth Bi₇ˍₓLaₓTi₄NbO₂₁ ceramics

Abstract

The dielectricpermittivity of Bi₇ˍₓLaₓTi₄NbO₂₁ (x=0–1.75)ceramics at ambient temperature is stable in a wide range of frequencies and can be modulated from 150 to 320 by compositional modification. With increasing La³⁺ content, both the phase transition temperatures downshift and the phase transition peaks become diffusive when x⩾1.00. The P-E hysteresis loops indicated that the remanent polarization2Pr of Bi₆.₅La₀.₅Ti₄NbO₂₁ has a maximum of 24.4μC/cm2. The Raman scattering experiments revealed that the Bi3+ in [Bi2O2]2+ layers is substituted by La³⁺ when x⩾1.00 and there is no Bi³⁺ at the A sites being substituted further when x⩾1.50. Show more