title: Room temperature multiferroicity in Bi(4.2)K(0.8)Fe(2)O(9+δ).
abstract: Magnetoelectric multiferroics are materials that have coupled magnetic and electric dipole orders, which can bring novel physical phenomena and offer possibilities for new device functions. In this report, single-crystalline Bi(4.2)K(0.8)Fe(2)O(9+δ) nanobelts which are isostructural with the high-temperature superconductor Bi(2)Sr(2)CaCu(2)O(8+δ) are successfully grown by a hydrothermal method. The regular stacking of the rock salt slabs and the BiFeO(3)-like perovskite blocks along the c axis of the crystal makes the Bi(4.2)K(0.8)Fe(2)O(9+δ) nanobelts have a natural magnetoelectric-dielectric superlattice structure. The most striking result is that the bulk material made of the Bi(4.2)K(0.8)Fe(2)O(9+δ) nanobelts is of multiferroicity near room temperature accompanied with a structure anomaly. When an external magnetic field is applied, the electric polarization is greatly suppressed, and correspondingly, a large negative magnetocapacitance coefficient is observed around 270 K possibly due to the magnetoelectric coupling effect. Our result provides contributions to the development of single phase multiferroics.
authors: Hefei National Laboratory for Physical Sciences at Microscale, Department of Physics, CAS Key Lab Mat Energy Convers, University of Science and Technology of China , Hefei 230026, PR China.
authors: Si-Ning
authors: SN
authors: Dong
authors: Yi-Ping
authors: YP
authors: Yao
authors: Jian-Qi
authors: JQ
authors: Li
authors: Yuan-Jun
authors: YJ
authors: Song
authors: Yu-Kuai
authors: YK
authors: Liu
authors: Xiao-Guang
authors: XG
authors: Li