Relaxor-like Dielectric Behavior in Stoichiometric Sillenite Bi₁₂SiO₂₀

Abstract

A combination of fixed frequency dielectric measurements (103 to 106 Hz) and impedance spectroscopy reveal evidence of (nonferroelectric) relaxor-like behavior in the temperature range ∼600–750 K for the stoichiometric sillenite phase Bi12SiO20 (space group I23, a = 10.1034(5) Å). Variable temperature Raman Spectroscopy reveals significant changes associated with the Bi–O framework vibrations, and the relaxor-type behavior is attributed to noncorrelated local dipole moments associated with the BiO5E (E = 6s2 lone pair) units in the framework. Sillenites, therefore, represent another family of Bi-based oxides to exhibit relaxor-like dielectric behavior.

Electrical properties of bismuth ferrites: Bi2Fe4O9 and Bi25FeO39

“…We note that a similar effect has been seen in the stoichiometric sillenite phase, Bi 12 SiO 20 [47].…”

Electrospun sillenite Bi12MO20 (M = Ti, Ge, Si) nanofibers: general synthesis, band structure, and photocatalytic activity

“…19 The BMOs are of great importance because of their interesting photorefractive, photochromic, dielectric properties [20][21][22] and promising industrial applications in the fields of optical signal processing, phase conjugation, image amplification, holographic data storage, real-time holography, and optical communications. 22,23 In recent years, the photocatalytic properties of BMOs have also attracted increasing attention for decomposing organic pollutants. For instance, Yao et al 24 reported that Bi 12 TiO 20 with a band gap of about 2.4 eV and Ba-doped Bi 12 TiO 20 (ref.…”

Electrical properties of epoxy-glue/(Bi12MnO20–BiMn2O5) composite

“…It corresponds to the electric conductivity relaxation process, which was determined in the former works. 14,19,21 The epoxy-glue sample shows two orders lower electric permittivity in comparison to BM ceramics ( Figure 5(b)). The addition of BM to the epoxy-glue matrix resulted in e 0 (T) decrease by two orders in respect to the reference BM ( Figure 5(c)).…”

“…This phase shows indirect gap equal to 0.78 eV 20 than the Bi 12 MnO 20 phase, with E gap ¼ 1.66 eV. 10,21 Moreover, BiMn 2 O 5 exhibits antiferromagnetic order below $40 K. 20,22 The non-polar BM ceramics, exhibited high value electric permittivity, " 0 & 10 3 to 10 4 , and dielectric losses coefficient, tan & 1-20, in vicinity of room temperature, dependably of measuring frequency. It has been determined that BM exhibits two relaxation processes, which correspond to activation energy, E A ¼ 0.19 eV and 0.24 eV, respectively.…”