Temperature stable dielectric properties of lead-free BiFeO₃–BaTiO₃ modified with LiTaO₃ ceramics

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>LiTaO<SUB>3</SUB> (LT)-modified (1 − <I>x</I>)(0.675BiFeO<SUB>3</SUB>–0.325BaTiO<SUB>3</SUB>) + 0.6 mol% MnO<SUB>2</SUB> + 0.4 mol% CuO (BFBTMC–<I>x</I>LT, where <I>x</I> = 0–0.030) ceramics were synthesized by solid state reaction method. The crystal symmetry, ferroelectric response, and temperature stable dielectric properties were investigated as a function of different LT-content. The X-ray diffraction study of BFBTMC–LT piezoceramics revealed no remarkable variation in the crystal symmetry. The value of maximum polarization (<I>P</I> <SUB>m</SUB> ≈ 24 μC/cm<SUP>2</SUP>) and remnant polarization (<I>P</I> <SUB>r</SUB> ≈ 18 μC/cm<SUP>2</SUP>) were obtained at BFBTMC–0.010LT composition. The maximum temperature of permittivity (<I>T</I> <SUB>max</SUB>) decreased by the addition of LT-content in BFBTMC materials. The un-doped sample was ferroelectric; a change to relaxor behavior occurred by the addition of LT-content, with broad frequency dependent curves of dielectric mid-value permittivity (ε<SUB>rmid</SUB>) and tangent loss as a function of temperature. A significant enhancement occurred at 3 mol% LT-modified BFBTMC ceramics, with ε<SUB>rmid</SUB> = 5000 ± 9.5% (250–450 °C at 1 kHz). These results are favorable for practical applications in high temperature dielectrics.</P> <P><B>Highlights</B></P> <P> <UL> <LI> LiTaO<SUB>3</SUB>-modified BiFeO<SUB>3</SUB>–BaTiO<SUB>3</SUB> dielectric ceramics were prepared. </LI> <LI> Easy and reproducible solid state reaction method was used. </LI> <LI> Temperature stable dielectric of 5000 ± 9.5% was achieved in the range 250–450 °C. </LI> </UL> </P>