Dielectric behaviors of Aurivillius Bi5Ti3Fe0.5Cr0.5O15 multiferroic polycrystals: Determining the intrinsic magnetoelectric responses by impedance spectroscopy.
Dielectric behaviors of Aurivillius Bi5Ti3Fe0.5Cr0.5O15 multiferroic polycrystals: Determining the intrinsic magnetoelectric responses by impedance spectroscopy.
复制标题
Aurivilius Bi5Ti3Fe0.5Cr0.5O15 多铁性多晶的介电行为：通过阻抗谱测定本征磁电响应
DOI：
10.1038/srep17846
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发表时间：
2015-12-07
影响因子：
4.6
通讯作者：
Chu J
中科院分区：
文献类型：
--
作者：
Bai W;Chen C;Yang J;Zhang Y;Qi R;Huang R;Tang X;Duan CG;Chu J
60年前由Aurivillius开创的铋层铁电体（BLF）由于其无疲劳、无铅、高居里温度，特别是强磁电效应，近年来得到了复兴。然而，识别的内在ME性质和带电缺陷偶极子诱导的弛豫和自旋相关行为之间的内在联系仍然是一个艰巨的任务。在这里，我们报告了一个定量分析，以揭示本征自旋晶格耦合在Aurivillius铬掺杂的Bi 5 Ti 3FeO 15（BTFCO）多铁性多晶。通过介电模量、阻抗谱和等效电路模型系统地研究了Aurivillius BTFCO多晶的介电响应，阐明了晶粒内部发生的两种不同的介电弛豫过程。其中一个弛豫过程与Fe ~（3+）和Fe ~（2+）之间的局域电子转移有关，另一个弛豫过程则是Fe ~（3+）和Fe ~（2+）之间的局域电子跳跃和Cr ~（3+）和Cr ~（6+）之间的短程空穴迁移的竞争作用。本征介电常数的变化明确地证实了BTFCO多晶体中自旋和偶极有序之间的耦合。这些结果提供了一个重要的途径，确定的内在和外在的信号的电和ME响应，并将给予显着的推动，探索ME电子器件的Aurivillius材料。
Bismuth layer ferroelectrics (BLFs) pioneered by Aurivillius about sixty years ago have been revived recently because of the fatigue- and lead-free behaviors and high Curie temperature and especially the robust magnetoelectric (ME) effect. However, discerning the intrinsic ME nature and the inherence between charged defect dipole induced relaxation and spin-related behaviors are still an arduous task. Here, we report a quantitative analysis to reveal the intrinsic spin-lattice coupling in Aurivillius Cr-doped Bi5Ti3FeO15 (BTFCO) multiferroic polycrystals. Dielectric responses are systemically investigated by the temperature-dependent dielectric, module, impedance spectroscopy and equivalent circuit model and two different dielectric relaxation processes occurred in grain interior of Aurivillius BTFCO polycrystals are clarified. One relaxation is proposed to associate with localized transfer of electrons between Fe3+ and Fe2+ while another one arises from the competition interaction of localized hopping of electrons between Fe3+ and Fe2+ and short-range migration of holes between Cr3+ and Cr6+. The variation of the intrinsic permittivity unambiguously confirms the coupling between spin and dipolar orderings in BTFCO polycrystals. These results offer a vital avenue for identifying the intrinsic and extrinsic signals of the electric and ME responses and will give significant impetus to exploring the ME electronic devices of Aurivillius materials.