Effect of octahedron tilt on the structure and magnetic properties of bismuth ferrite

Multiferroic BiFeO3-based ceramics were synthesized using the rapid liquid-phase sintering method. The rare-earth ion (Sm3+, Gd3+, Y3+) doping causes structural distortion without changing the intrinsic rhombohedral perovskite structure. Raman analysis shows that the effect of doping on E modes is greater than A1 modes, and the microstructure of FeO6 octahedron can be regulated by ion doping. A-site trivalent ion doped ceramics exhibit improved magnetism compared with pure BiFeO3 ceramic, which originated from the suppressed spiral spin structure of Fe ions. The tilt of FeO6 octahedron as a typical structure instability causes the anomalous change of the imaginary part of permittivity at high frequency, and doped ceramics exhibit natural resonance around 16–17 GHz.

A Study of Multiferroic BiFeO3/Epoxy Resin Composite as Potential Coating Materials for Microwave Absorption

A single layer of BiFeO3 (BFO)/epoxy resin composite with thickness of 3 mm was fabricated by polymerized 70 wt% of sintered BFO as fillers and 30 wt% of epoxy resin polymer as matrix. The electromagnetic and the microwave absorption properties of BFO/epoxy resin composite were reported. The reflection loss (RL) of the same composite sample was measured by two different techniques of measurement, S11a parameter (without metal backed reflector) and S11b parameter (with metal backed reflector) in the range of 8-18 GHz using a network analyzer. Minimum RL (RLmin) from S11b parameter for BFO/epoxy resin composite with metal backed is lower than the RLmin from S11a composite without metal backed reflector. In details, the results showed BFO/epoxy resin composite with metal backed can achieve a strong absorption with RLmin of -40.5 dB over a 1.31 GHz bandwidth.

Thermophysical properties of BiFeO3/REE multiferroics in a wide temperature range

The paper presents the results of a comprehensive study of the thermophysical properties (thermal conductivity, thermal diffusivity, heat capacity) of high-temperature multiferroic BiFeO3 modified with rare-earth elements (REEs) (La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Lu). The regularities of the formation of the mentioned characteristics were established. The assumptions about the nature of the observed phenomena were suggested.

Anisotropic superconductivity induced by periodic multiferroic domain patterns

The competition between order parameters, such as ferroelectricity, ferromagnetism, and superconductivity, is one of the most fascinating topics in condensed matter physics. Here, we report intriguing anisotropic superconductivity in YBa2Cu3O7 − x films induced by a multiferroic, BiFeO3, with periodic domain patterns. The anisotropic superconductivity was investigated by transport measurements and supported by phase-field simulations, and then the detailed local electronic structures were revealed by cross-sectional scanning tunneling microscopy. We found that the oxygen redistribution in YBa2Cu3O7 − x modulated by the ferroelectric polarization in BiFeO3 was the key mechanism driving this anisotropic superconductivity. The presented heteroarchitecture of a high-temperature superconductor and a domain-engineered multiferroic provides a new approach to tune superconductivity and offers potential advantages for the design of future multifunctional devices.