Room-temperature magnetoelectric coupling in single-phase BaTiO3-BiFeO3 system

Abstract

In this paper, single-phase multiferroic ceramics of (1 − x) BaTiO3 − x BiFeO3 (BT − x BFO) were synthesized by solid-solution method in the wide range of material composition (x = 0.025 – 1.0). The changes in crystal structure were confirmed via X-ray diffractions (XRD) and atomic pair distribution functions (PDFs). The room-temperature ME coupling was found to exhibit significant magnitude in the narrow composition window (x = 0.71 – 0.8) where the average crystal structure was found to be rhombohedral. Especially, the BT – 0.725 BFO ceramics containing local monoclinic distortions within rhombohedral phase were found to exhibit high room-temperature ME coefficient (αME) of 0.87 mV/cm·Oe with high piezoelectric properties (g33 = 18.5 × 10 mV m N−1 and d33 = 124 pC N−1). We believe that the high room-temperature ME coupling in single-phase lead-free BT-BFO ceramics provides a possibility of developing electrically or magnetically tunable thin-film devices.

Photoconductivity and photo-detection response of multiferroic bismuth iron oxide

“…[1][2][3] It different functional properties and cross coupled ferroic order parameters make it a potential candidate for nonvolatile memory elements, optical memory devices, abovebandgap photovoltaic devices, micro/nano electromechanical systems, magnetic field sensors, etc. [4][5][6][7][8][9][10] The optical properties of BiFeO 3 (BFO) are also different from most of the perovskite ferroelectric due to its lower bandgap (2.6-2.9 eV) and conducting domain walls. 11,12 Clark and Robertson 13 predicted both direct and indirect bandgaps around 2.5 eV using band structure model, and afterward Ihlefeld et al 14 reported a direct-gap transition at 2.74 eV; however, recently we also found a direct bandgap of 2.55 eV at T ¼ 295 K, an indirect band edge at 2.67 eV.…”

Giant magnetoelectric coupling interaction in BaTiO3/BiFeO3/BaTiO3 trilayer multiferroic heterostructures

“…31 The observed value of ME coupling coefficient in our samples is significantly larger than the reported value of 7 mV/cm Oe for single phase bulk BiFeO 3 sample and 124 mV/cm Oe for 0.9 BFO -0.1 BTO ceramic composite thin films and bulk samples. [33][34][35][36] Such substantially high magnetoelectric coupling coefficient values obtained at room temperature paves the way to fabricate new type of electric-field controlled magnetic random access memory (MERAM), magnetoelectric sensors, voltage tunable RF/microwave signal processing devices, and spintronic devices…”

Structure and Mössbauer spectroscopy studies of mechanically activated (BiFeO3)1−x-(BaTiO3)x solid solutions

“…As reported in Refs. [5,6, and references therein], rhombohedral symmetry is maintained for x = 0-0.3, after which cubic symmetry predominates up to x = 0.93. For x > 0.93 and for a pure BaTiO 3 compound, the structure is tetragonal.…”

“…This may be achieved, for example, by structural modifi cations or deformations introduced by cation substitution or doping [5]. Therefore, a solid solution of BiFeO 3 [6].…”