Vortex switching in ferroelectric nanodots and its feasibility by a homogeneous electric field: Effects of substrate, dislocations and local clamping force
Vortex switching in ferroelectric nanodots and its feasibility by a homogeneous electric field: Effects of substrate, dislocations and local clamping force
复制标题
铁电纳米点中的涡旋切换及其均匀电场的可行性：基底、位错和局部夹紧力的影响
DOI：
10.1016/j.actamat.2015.01.041
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发表时间：
2015-04-15
期刊：
影响因子：
9.4
通讯作者：
Zheng, Yue
中科院分区：
文献类型：
--
作者：
Chen, W. J.;Zheng, Yue
考虑到不对称机械场的影响（例如，由衬底、位错和局部夹持力引起），我们进行相场模拟来研究铁电纳米点中涡旋畴结构的演化。对于不同机械约束下的纳米点，其畴演化特征，例如，对磁滞回线、畴型和演化路径进行了全面的揭示和比较。我们的计算表明，衬底、位错和局部夹持力显着影响纳米点的畴演化，导致与独立纳米点不同的行为。对于这样的系统，由于不对称的机械场打破了涡旋畴成核和生长的对称性，涡旋畴结构的演化由特定区域的偶极子主导，我们称之为“主导偶极子”。其结果是，纳米点表现出不同的演化路径，并通过卷曲电场的涡旋开关的矫顽场降低相比，独立的。更重要的是，对于这样的系统，可以通过控制主导偶极子的流动方向来实现由均匀电场的单涡旋开关。我们的研究提供了有用的信息，在铁电纳米结构中的涡旋畴结构的实际控制由常规的静电场。(C)2015 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
Taking into account the effects of asymmetric mechanical fields (e.g., caused by substrate, dislocations and local clamping force), we conduct phase-field simulations to investigate the evolution of vortex domain structure in ferroelectric nanodots. For nanodots under different mechanical constraints, their characteristics of the domain evolution, e.g., the hysteresis loop, the domain patterns and the evolution paths, have been revealed and compared comprehensively. Our calculations show that substrate, dislocations and local clamping force significantly affect the domain evolution of the nanodots, leading to distinct behaviors from those of the free-standing ones. For such systems, as the asymmetric mechanical field breaks the symmetry of vortex domain nucleation and growth, the evolution of the vortex domain structure is dominated by a specific region of dipoles, which we name "dominant dipoles". As a result, the nanodots exhibit distinct evolution paths, and the coercive field of vortex switching by a curled electric field is reduced compared with the free-standing ones. More importantly, for such systems, it is possible to realize single-vortex switching by a homogeneous electric field through controlling the flowing direction of the dominant dipoles. Our study provides useful information on the practical control of the vortex domain structure in ferroelectric nanostructures by conventional electrostatic fields. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.