Electrical Properties Of Barium Calcium Zirconate Titanate Based Ceramics And Thin Films

Recently, because of the special mechanical, thermal, electrical, optical and other properties or the coupling function between the mechanical, electrical, acoustic, optical, thermal, magnetic, functional ceramics are widely used in the the electric energy storage, energy conversion, the large displacement actuators and other fields. In the past decade, the increasingly strong awareness of environmental protection make the lead-free functional ceramics gaining more and more attention. Barium zirconate titanate and modified by doping has been recognized because of its excellent electrical performance and mature preparation process, such as (Ba1-xCax)(Zr1-y,Tiy)03(BCZT) and its doping. We use the traditional solid phase method to prepare (Ba0.85Ca0.15)(Zr0.10Ti0.90)O3-xmol%of Mn (0≤x≤0.5) ceramic and we use sol-gel method (Ba0.90Ca0.10)(Zr0.25Ti0.75)O3thin films and studied their electrical properties.Relaxation characteristics was shown the dielectric temperature characteristics of the samples sintered1200℃measured at different frequencies. According to the formula of Maxwell Wagner theory and Vogel-Fulcher (VF) relationship, we obtain the value of activation energy Ea=1.15eV. The maximal dielectric constant (ε) of the BCZT ceramics increases rapidly with the increase of sintering temperature and reaches the maximum value of9530at1300℃, then decrease with further increase of sintering temperature. We take charge the permittivity by Curie-Weiss (modified) Law. All the BCZT ceramic sintered in different times shows good ferroelectric properties, and their remanent polarization Pr and coercive field Ec show regularity change with different sintering temperature, respectively. The piezoelectric constant d33increase with increasing the sintering temperature as well, from the value of81.1at1200℃to a maximum value of291pC/N respectively, at1270℃.In order to understand the impact on the performance of Manganese dioxide doped the the pure BCZT ceramics,(Ba0.85Ca0.15)(Zr0.10Ti0.90) O3-x mol%MnO2was (x=0.1,0.2,0.3,0.4,0.5) ceramics were prepared. The results shows that MnO2had a great influence on the dielectric properties of the BCZT ceramics. SEM is made on the ceramic samples with different content of Mn found that when x≈0.3, manganese ion doped in to the grains of BCZT ceramic and be saturation, for x>0.3manganese ions doped into the grain boundary. First of all, manganese doping reduce the dielectric constant of BCZT ceramic. According to the modified Curie-Weiss law, we get the diffuseness constant y of the BCZT-xMn mol%ceramic increases from1.80to1.94as the Mn content increases from0to0.5%. And then the pyroelectric was research, the pyroelectric coefficient was calculated.In addition, the phase, microstructure, dielectric and ferroelectric properties of thin films with and without LaNiO3buffer layer prepared by a sol-gel process. We studied the influence of the nickel-lanthanum (LaNiO3) buffer layer to thin films performance. The ferroelectric properties are also very different, and finally for the first time to study the magnetic properties of this series of films and detailed analysis had been done.