Magnetic Field-Induced Ferroelectric Switching in Multiferroic Aurivillius Phase Thin Films at Room Temperature
Magnetic Field-Induced Ferroelectric Switching in Multiferroic Aurivillius Phase Thin Films at Room Temperature
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DOI：
10.1111/jace.12467
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发表时间：
2013-08-01
影响因子：
3.9
通讯作者：
Whatmore, Roger W.
中科院分区：
文献类型：
--
作者：
Keeney, Lynette;Maity, Tuhin;Whatmore, Roger W.
单相多铁性材料在未来的存储和传感应用中具有相当大的兴趣。采用化学溶液沉积法在c面蓝宝石上制备了Aurivillius相Bi 7 Ti 3Fe 3 O21和Bi6Ti2.8Fe1.52Mn0.68O18薄膜（每个半电池分别具有6个和5个钙钛矿单元）。超导量子干涉仪的磁测量结果表明，Bi_7 Ti_3Fe_3 O_（21）在35 K以下为弱铁磁性，而Bi_6 Ti_（2.8）Fe_（1.52）Mn_（0.68）O_（18）在室温下具有明显的面内铁磁性（M-s=0.74emu/g，H_（0（c））= 7 mT）。显微结构分析，再加上使用的数据的统计分析，使我们能够得出结论，铁磁性不源自第二相夹杂物，置信度为99.5%。压电响应力显微镜（PFM）表明，在这两种薄膜的室温铁电性，而PFM观察Bi6Ti2.8Fe1.52Mn0.68O18显示Aurivillius晶粒进行铁电畴极化开关所施加的磁场诱导。在这里，我们首次表明，Bi6Ti2.8Fe1.52Mn0.68O18薄膜是铁电和铁磁的，并在室温下证明磁场诱导的铁电极化在个别Aurivillius相晶粒的开关。
Single-phase multiferroic materials are of considerable interest for future memory and sensing applications. Thin films of Aurivillius phase Bi7Ti3Fe3O21 and Bi6Ti2.8Fe1.52Mn0.68O18 (possessing six and five perovskite units per half-cell, respectively) have been prepared by chemical solution deposition on c-plane sapphire. Superconducting quantum interference device magnetometry reveal Bi7Ti3Fe3O21 to be antiferromagnetic (T-N= 190K) and weakly ferromagnetic below 35K, however, Bi6Ti2.8Fe1.52Mn0.68O18 gives a distinct room-temperature in-plane ferromagnetic signature (M-s=0.74emu/g, H-0(c)=7mT). Microstructural analysis, coupled with the use of a statistical analysis of the data, allows us to conclude that ferromagnetism does not originate from second phase inclusions, with a confidence level of 99.5%. Piezoresponse force microscopy (PFM) demonstrates room-temperature ferroelectricity in both films, whereas PFM observations on Bi6Ti2.8Fe1.52Mn0.68O18 show Aurivillius grains undergo ferroelectric domain polarization switching induced by an applied magnetic field. Here, we show for the first time that Bi6Ti2.8Fe1.52Mn0.68O18 thin films are both ferroelectric and ferromagnetic and, demonstrate magnetic field-induced switching of ferroelectric polarization in individual Aurivillius phase grains at room temperature.