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

Abstract

BiAlO 3 is a perovskite ferroelectric with a high Curie temperature above 520°C. However, it is difficult to prepare pure perovskite phase by the conventional method. In this experiment, BaTiO 3 has been selected as host to incorporate BiAlO 3 , and the nominal binary system of (1-x)BaTiO 3 -xBiAlO 3 has been investigated with regard to its Curie temperature (T c ) and dielectric relax behaviors. It was found that the pure perovskite phase can be retained below x00.08. However, the value of T c in the system doesn't follow the normal Vegard's law, on the contrary, shows the decreasing trend with the increase of x. According to the compared experiments about Bi 3+ and Al 3+ doping in BaTiO 3 , it can be safely concluded that the combined substitution of Bi 3+ and Al 3+ played the dominant role to decrease the T c and increase the relaxor behavior in (1-x) BaTiO 3 -xBiAlO 3 system.

Structure and Dielectric Properties of BaTiO3–BiYO3 Perovskite Solid Solutions

“…Maximum dielectric constant and T m at 1 MHz for the studied compositions are listed in Table , where the T m was found to first increase and then decrease with the increase in BY content, being consistent with the literature . The same phenomena was also reported in BaTiO 3 –(Na 0.5 Bi 0.5 )TiO 3 , BaTiO 3 –BiFeO 3 , and BaTiO 3 –(Na 1/4 Bi 3/4 )(Mg 1/4 Ti 3/4 )O 3 systems, but showing a contrary behavior for BaTiO 3 –BiMeO 3 (Me = Al 3+ , Sc 3+ , (Ni 1/2 Ti 1/2 ) 3+ , (Mg 1/2 Ti 1/2 ) 3+ , (Zn 1/2 Ti 1/2 ) 3+14 ) systems when the doped level is low, which may be associated with the synthesis condition of Bi‐based compounds, such as normal solid‐state reactions or sintering at high temperature and high pressure.…”

Advances in lead‐free high‐temperature dielectric materials for ceramic capacitor application

“…Except for BiScO 3 , BiAlO 3 was also taken as end‐member to form solid solutions for capacitor applications. In 2010, our group designed the BaTiO 3 –BiAlO 3 (BT–BA) binary system and investigated its structure description and dielectric behaviours [39, 40]. The temperature‐dependent relative permittivity of 0.9BT–0.1BA composition depicts a typical relaxor behaviour with noticeable frequency dispersion and strongly diffusive and broad dielectric maximum, which suggests the positive effect of BA on BT ceramic for temperature stability.…”

A Unique Mechanism for Dielectric-Temperature Stability of BaTiO3-Based Ceramics Using Ba(OH)2/TiO2 Suspension

“…The main peaks can be indexed as a typical BaTiO 3 phase structure for all samples types and maintained in the pseudocubic phase. In previous research studies, Huichun 14 and Hou 15 reported that single perovskite phase formation of (1 − x)BT−xBA ceramics can be retained in a low compositional range of 0 ≤ x ≤ 0.08. Such low solubility limits explain the appearance of BaAl 2 O 4 -type secondary phase at 2θ = 28°and 34°(displayed in Figure 4a, b).…”