Nat Mater. 2010 Apr;9(4):309-14. doi: 10.1038/nmat2703. Epub 2010 Feb 28.
Multiferroics, where (anti-) ferromagnetic, ferroelectric and ferroelastic order parameters coexist, enable manipulation of magnetic ordering by an electric field through switching of the electric polarization. It has been shown that realization of magnetoelectric coupling in a single-phase multiferroic such as BiFeO(3) requires ferroelastic (71 degrees, 109 degrees) rather than ferroelectric (180 degrees) domain switching. However, the control of such ferroelastic switching in a single-phase system has been a significant challenge as elastic interactions tend to destabilize small switched volumes, resulting in subsequent ferroelastic back-switching at zero electric field, and thus the disappearance of non-volatile information storage. Guided by our phase-field simulations, here we report an approach to stabilize ferroelastic switching by eliminating the stress-induced instability responsible for back-switching using isolated monodomain BiFeO(3) islands. This work demonstrates a critical step to control and use non-volatile magnetoelectric coupling at the nanoscale. Beyond magnetoelectric coupling, it provides a framework for exploring a route to control multiple order parameters coupled to ferroelastic order in other low-symmetry materials.
多铁性材料中（反）铁磁、铁电和铁弹序参量共存，可通过电位移的反转来实现对磁有序的操控。已有研究表明，单相多铁材料如 BiFeO(3) 中磁电耦合的实现需要铁弹（71 度、109 度）而非铁电（180 度）畴的反转。然而，单相体系中这种铁弹反转的控制一直是一个重大挑战，因为弹性相互作用往往会使较小的反转体积失稳，导致在零电场下铁弹的反向反转，从而使非易失性信息存储消失。受我们的相场模拟的指导，我们在此报告了一种通过消除导致反向反转的应力诱导不稳定性来稳定铁弹反转的方法，方法是使用孤立的单畴 BiFeO(3) 岛。这项工作展示了控制和利用纳米尺度非易失性磁电耦合的关键步骤。除了磁电耦合之外，它还为探索控制其他低对称性材料中与铁弹序相关的多个序参量的途径提供了一个框架。
