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.
Sci Rep. 2013;3:1245. doi: 10.1038/srep01245. Epub 2013 Feb 13.
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.
磁电多铁材料具有耦合的磁偶极子和电偶极子序，这可以带来新的物理现象，并为新的器件功能提供可能性。在本报告中，通过水热法成功生长出与高温超导体 Bi(2)Sr(2)CaCu(2)O(8+δ)同构的单晶 Bi(4.2)K(0.8)Fe(2)O(9+δ)纳米带。晶体沿 c 轴的盐片和 BiFeO(3)类钙钛矿块的规则堆叠使 Bi(4.2)K(0.8)Fe(2)O(9+δ)纳米带具有天然的磁电-介电超晶格结构。最显著的结果是，由 Bi(4.2)K(0.8)Fe(2)O(9+δ)纳米带制成的块状材料在室温附近具有多铁性，同时伴有结构异常。当施加外磁场时，电极化大大抑制，相应地，在 270 K 左右观察到大的负磁电容系数，这可能归因于磁电耦合效应。我们的结果为单相多铁材料的发展做出了贡献。
