Dielectric properties and relaxor behavior of a new (1−x)BaTiO3–xBiAlO3 solid solution

Abstract

A new lead-free perovskite solid solution of ͑1−x͒BaTiO 3 -xBiAlO 3 ͑x = 0.02, 0.05, 0.10, and 0.15͒ that exhibits ferroelectric properties and relaxor behavior has been synthesized by solid state reactions. X-ray diffraction patterns show a transformation from the tetragonal symmetry into a rhombohedral symmetry as a result of the substitutions of Bi 3+ on the A site and Al 3+ on the B site in the crystal lattice of BaTiO 3 . The temperature and frequency dependences of the dielectric constant indicate a crossover from a normal ferroelectric to relaxor behavior. The degree of deviation from the Curie-Weiss law is found to increase with the increasing amount of BiAlO 3 . The high-temperature slope of the dielectric peak for x = 0.05, 0.1 and, 0.15 can be well described by a Lorenz-type relation. Typical relaxor behavior is observed for x = 0.15 with the temperature of the dielectric peak T m = 360 K at 1 kHz, while ferroelectric hysteresis loop is displayed at room temperature. This suggests that the long-range polar order from the end member BaTiO 3 persists and coexists with polar nanoregions induced by the chemical disorder following the coupled substitutions in the solid solution.

Ferroelectric Relaxor Behavior and Spectroscopic Properties of Ba<SUP>2+</SUP> and Zr<SUP>4+</SUP> Modified Sodium Bismuth Titanate

“…This type of temperature and frequency dependence of M 11 arises due to the distribution of relaxation times in the material because of cationic disorder at both A-and B-sites in this composition. Similar behaviour has been noticed in both M 1 , M 11 Vs log F in the composition for 0.12BNBZT…”

“…[7] In recent years, therefore, some countries have required all new electronic products to be lead-free for the environmental protection and human health. [8] Hence, many studies are focused on the BaTiO 3 -based materials such as BaTiO 3 -BaZrO 3 , [9] BaTiO 3 -BaSnO 3 , [10] BaTiO 3 -BiAlO 3 , [11] and BaTiO 3 -CaTiO 3 -SrTiO 3 [12] because these BaTiO 3 -based lead-free relaxor ferroelectrics show relatively high dielectric and…”

The variation of Curie temperature and dielectric relaxor behaviour in the nominal (1-x)BaTiO3-xBiAlO3 system

“…So it was expected that this method can be extended to the preparation of pure BiAlO 3 perovskie phase, meanwhile, the properties of both the host compound and BiAlO 3 could be modified. In this way, many solid solutions, such as BaTiO 3 -BiAlO 3 [7], (Na 0.5 Bi 0.5 )TiO 3 -BiAlO 3 [8], (Na 0.5 K 0.5 )NbO 3 -BiAlO 3 [9] and PbTiO 3 -BiAlO 3 [10], have been proposed. However, it should be noted that the Curie temperatures of these solid solutions strongly decrease with the increase of BiAlO 3 content, even lower than that of the host compound.…”

Simultaneous achievement of high dielectric constant and low temperature dependence of capacitance in (111)-oriented BaTiO3-Bi(Mg0.5Ti0.5)O3-BiFeO3 solid solution thin films

“…The low temperature dependence of the dielectric properties for the pseudocubic phase is in good agreement with previous reports for sintered bodies formed using BaTiO 3 -BiMO 3 solid solutions. [13][14][15][16][17][18][19] This is considered to be related to the relaxed behavior of these solid solutions, and the diffused temperature dependence of ε r , which reduces the overall temperature dependence of ε r . 20 In contrast, Mitsui et al reported that the maximum ε r was observed at more than 400 • C for x = 0.60.…”

“…11,12 Also, a low ε r temperature dependence has been reported for solid solution systems of BaTiO 3 and Bi-based perovskite oxides with pseudocubic structures at room temperature. Sintered bodies of BaTiO 3 -BiMO 3 [where M = Sc 3+ , Al 3+ , (Mg 0.5 Ti 0.5 ) 3+ , and (Zn 0.5 Ti 0.5 ) 3+ ] with pseudocubic symmetry show particularly high ε r stability at temperatures up to 400 • C. [13][14][15][16][17][18][19] In a previous study, we investigated the dielectric properties of ternary BaTiO 3 -Bi(Mg 0.5 Ti 0.5 )O 3 -BiFeO 3 solid solution films prepared by chemical solution deposition (CSD) as alternatives to BaTiO 3 -based high-ε r materials. 20 This system has a wide compositional region with a pseudocubic symmetry between the tetragonal and rhombohedral symmetries at room temperature.…”