Growth of (111)-oriented BaTiO3–Bi(Mg0.5Ti0.5)O3 epitaxial films and their crystal structure and electrical property characterizations

Abstract

Epitaxial (1−x)BaTiO3−xBi(Mg0.5Ti0.5)O3 films with x = 0 − 0.9 were grown on (111)cSrRuO3//(111)SrTiO3 substrates by pulsed laser deposition (PLD). Plotting the temperature where dielectric constant reaches a maximum {T[ɛr(max.)]} versus Bi(Mg0.5,Ti0.5)O3 content present minimum at x = 0.1. On the other hand, the remanent polarization (Pr) and the effective transverse piezoelectric constant [d33(eff.)] showed minimum at 0.1 and 0.2, respectively, but increased with the increase of x in (1−x)BaTiO3−xBi(Mg0.5Ti0.5)O3 above these values. These results show the simultaneous increase of T[ɛr(max.)] and d33(eff.) for the films above x = 0.2 that normally showed treads off characteristics.

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

“…with temperatures in the range from room temperature to 400 • C are −78.5, −51.7, and 85% for the reported (Ba 0.3 Sr 0.7 )TiO 3 , SrTiO 3 , and 0.5BaTiO 3 -0.5Bi(Mg 0.5 Ti 0.5 )O 3 structures, respectively. 10,19 The absolute values for the present pseudocubic films, which are shown in Figure 2(a), are significantly smaller than those for other perovskite oxides. In the following, we investigate the absolute value of the temperature dependence of the capacitance in the range between room temperature and a specific temperature T, i.e., |TCC T | , as defined by Raengthon et al: 25 We monitored the evolution of |TCC 250 • C | and |TCC 400 • C | in particular; they were estimated at 250 • C and 400 • C, respectively, as a function of x in (0.90-x)BaTiO 3 -0.10Bi(Mg 0.5 Ti 0.5 )O 3 -xBiFeO 3 (see Fig.…”

“…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.…”

Dielectric properties of BaTiO₃–Bi(Mg_1/2Ti_1/2)O₃ films with preferential crystal orientation

“…24) The difference can arise from their crystal orientation, which is closely related to crystallographic anisotropy of dielectric permittivity 35)37) or clamping effects that induce (or release) inplane residual stress, 24),38),39) as frequently discussed for epitaxial films of other perovskite-based materials. Therefore, we fabricated BTBMT films with different crystal orientation, i.e., randomly-oriented and preferential (100)-and (111)-oriented films, for evaluating the orientation dependency of their dielectric and ferroelectric properties.…”

“…Combination with other perovskite compounds, such as SrTiO 3 , revealed the relaxor-type ¾ r ¹ T behavior with higher ¾ r of up to 1500. Also in our research, thin-film capacitors of BTBMT solid solution were fabricated by pulsed laser deposition (PLD) 24) and chemical solution deposition (CSD), 25) which exhibited suppressed TCC behavior together with ¾ r = 4001000. These properties will be more suitable for constructing high-permittivity dielectric capacitors with stable performance against temperature changes, compared with those of conventional materials.…”