Pan Dan-Feng, Zhou Ming-Xiu, Lu Zeng-Xing, Zhang Hao, Liu Jun-Ming, Wang Guang-Hou, Wan Jian-Guo
National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, 210093, China.
Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky, 40506-0055, USA.
Nanoscale Res Lett. 2016 Dec;11(1):318. doi: 10.1186/s11671-016-1534-2. Epub 2016 Jun 30.
Multiferroic La-doped BiFeO3 thin films have been prepared by a sol-gel plus spin-coating process, and the local magnetoelectric coupling effect has been investigated by the magnetic-field-assisted scanning probe microscopy connected with a ferroelectric analyzer. The local ferroelectric polarization response to external magnetic fields is observed and a so-called optimized magnetic field of ~40 Oe is obtained, at which the ferroelectric polarization reaches the maximum. Moreover, we carry out the magnetic-field-dependent surface conductivity measurements and illustrate the origin of local magnetoresistance in the La-doped BiFeO3 thin films, which is closely related to the local ferroelectric polarization response to external magnetic fields. This work not only provides a useful technique to characterize the local magnetoelectric coupling for a wide range of multiferroic materials but also is significant for deeply understanding the local multiferroic behaviors in the BiFeO3-based systems.
通过溶胶-凝胶旋涂工艺制备了多铁性La掺杂BiFeO₃薄膜，并利用与铁电分析仪相连的磁场辅助扫描探针显微镜研究了局部磁电耦合效应。观察到了局部铁电极化对外加磁场的响应，并获得了约40 Oe的所谓优化磁场，此时铁电极化达到最大值。此外，我们进行了磁场依赖的表面电导率测量，并阐明了La掺杂BiFeO₃薄膜中局部磁电阻的起源，这与局部铁电极化对外加磁场的响应密切相关。这项工作不仅为表征广泛的多铁性材料的局部磁电耦合提供了一种有用的技术，而且对于深入理解BiFeO₃基体系中的局部多铁性行为也具有重要意义。
