RbBiNb₂O₇: A New Lead-Free High-T_c Ferroelectric

Abstract

RbBiNb2O7 ceramic is synthesized by solid state reaction of stoichiometric quantities of Rb2CO3, Bi2O3, and Nb2O5 (1000 °C, 24 h) and characterized by powder XRD, Raman scattering spectroscopy, and electrical measurements.

Octahedral tilting and ferroelectricity in RbANb2O7(A = Bi, Nd) from first principles

“…In this sense, ferroelectricity in a Dion-Jacobson compound can be explained easily by hybrid improper ferroelectricity. More recently, Li et al reported the experimental realization of high-T c ferroelectric behavior of a RbBiNb 2 O 7 bulk material [32]. The ferroelectric transition temperature of 945°C was confirmed by temperature dependent dielectric constant experiments, Raman experiments, and piezoelectric constant experiments.…”

“…The spontaneous polarization of the Bi and Nd compound was 35.72 μC/cm 2 and 24.53 μC/cm 2 , respectively. Note that the experimental spontaneous polarization value of the Bi compound with a polycrystalline form was approximately 10 μC/cm 2 [32]. In terms of the tilting angle (shown in Table I), the c + tilting angle for the Bi compound was similar to that of the Nd compound (10.99 vs 10.72), whereas the a − tilting angle for the Bi compound was smaller than that of the Nd compound (5.98 vs 7.25).…”

Ruddleson-Popper phase SnO(SnTiO3)n: Lead-free layered ferroelectric materials with large spontaneous polarization

“…Actually, [110] polarization widely exists in many perovskite related layered compounds as ground state, such as Aurivillius phase SrBi 2 Ta 2 O 9 , 34 RP phase SrO(SrTiO 3 ) n , 21 and DionÀJacobson type RbBiNb 2 O 7 . 35 The total energy of Aba2 phase decreases with substrate lattice constant, because that compressive strain favors octahedral rotations, as shown in Fig. S4.…”

Phase Transition Behavior of the Layered Perovskite CsBi0.6La0.4Nb2O7: A Hybrid Improper Ferroelectric

“…The concept of HIFs has been typically applied by theorists to mean the imposition of a stable polar ground state in a crystal via the coupling of two or more intrinsically non-polar modes with a polar mode ("tri-linear coupling"), with no requirement for an experimentally-realized polarization reversal. However, such experimental demonstrations of polarization-field hysteresis have now been reported, for example in the Ruddlesden-Popper (RP) phase Ca 3 Ti 2 O 7 [8] and the Dion-Jacobson (DJ) phase RbBiNb 2 O 7 [9].…”

“…Prior to the recent flurry of work from the theoretical standpoint, it was known that ferroelectricity, or at least polarity, co-existed with octahedral tilting in several layered perovskites, the most well-established being the Aurivillius family, exemplified by SrBi 2 Ta 2 O 9 and Bi 4 Ti 3 O 12 [10]. Snedden et al [11] later made the intuitive link between the nature of octahedral tilting in the DJ phase CsBiNb 2 O 7 and that in SrBi 2 Ta 2 O 9 ; both have a tilt system analogous to that described by the Glazer notation a − a − c + in ABX 3 perovskites.…”