Sillen–Aurivillius Intergrowth Phases as Templates for Naturally Layered Multiferroics

Abstract

The ferroelectric Sillen-Aurivillius phase Bi 5 PbTi 3 O 14 Cl, a layered structure containing three-layer perovskite-type blocks, has been modified by substituting magnetic transition metal cations M 3+ = Cr 3+ , Mn 3+ or Fe 3+ for 1 3 of the Ti 4+ cations, accompanied by co-doping of Bi 3+ for Pb 2+ . The aim of the modification was to produce naturally-layered ferroelectromagnetic compounds. Rietveld refinements against high-temperature synchrotron X-ray powder diffraction data show that the resulting new compounds Bi 6 Ti 2 MO 14 Cl undergo noncentrosymmetric (P2an) to centrosymmetric (P4/mmm) ferroelectric phase transitions for Bi 6 Ti 2 CrO 14 Cl at 974.6(2) K, Bi 6 Ti 2 MnO 14 Cl at 913.5(6) K, and Bi 6 Ti 2 FeO 14 Cl at 1044.8(1) K. Ferroelectric properties were measured on Bi 6 Ti 2 FeO 14 Cl using piezoresponse force microscopy which showed typical ferroelectric hysteresis behaviour in the polarisation with varying field strength as well as a piezoelectric strain. Combined Rietveld refinements against X-ray and neutron powder diffraction data indicate a statistical 1:2 distribution of M 3+ and Ti 4+ across all three perovskite layers, resulting in highly strained structures (enhancing the ferroelectricity compared to Bi 5 PbTi 3 O 14 Cl) and pronounced spin-glass (cluster glass-type) behaviour below T irr (0) = 4.46 K that we have characterised by detailed magnetic susceptibility and heat capacity measurements.

Single Crystal Growth of Sillén–Aurivillius Perovskite Oxyhalides Bi4NbO8X (X = Cl, Br)

“…The single-crystal XRD on the platelet crystal revealed that a pseudo-merohedral twin is likely present with domains in the ab plane, in addition to the ferroelectric domains. We also report the growth of single crystal Bi 4 (n = 1, 2, 3, ...) constitutes a promising material platform not only for the photocatalysis but also for ferroelectric [24] or multiferroic properties [25]. We believe that the knowledge of single crystal growth obtained in this study on Bi 4 NbO 8 X can be applied to other Sillén-Aurivillius oxyhalide compounds.…”

Buried In-Plane Ferroelectric Domains in Fe-Doped Single-Crystalline Aurivillius Thin Films

“…[6][7][8][9] In the last years, layered oxides have attracted continuously growing attention for being a promising playground for the design of new multiferroic materials. 10,11 The structure of the layered oxides is typically composed by an alternation of perovskite blocks and spacing layers having a different structure, e.g. rock salt 12 or fluorite 13 , thus forming a superstructure.…”

Synthesis and cation distribution in the new bismuth oxyhalides with the Sillén–Aurivillius intergrowth structures

“…These structures can be designated as X m (m = 1 or 2 according to the number of anion sheets). 4 This already vast family, called Bipox (Bismuth perovskite oxyhalides), [11][12][13][14][15][16][17][18][19][20] comprise structures where the fluorite layers are separated alternatively by perovskite and halide layers as shown in Fig. 1.…”