Misirlioglu I B, Pintilie L, Alexe M, Hesse D
Faculty of Engineering and Natural Sciences, Sabanci University, Tuzla/Orhanli, Istanbul, 34956 Turkey.
NIMP, P.O. Box MG-7, Bucharest-Magurele, 077125 Romania.
J Mater Sci. 2009;44(19):5354-5363. doi: 10.1007/s10853-009-3451-6. Epub 2009 Oct 1.
Phase transition and field driven hysteresis evolution of a two-dimensional Ising grid consisting of ferroelectric-antiferroelectric multilayers that take into account the long range dipolar interactions were simulated by a Monte-Carlo method. Simulations were carried out for a 1 + 1 bilayer and a 5 + 5 superlattice. Phase stabilities of components comprising the structures with an electrostatic-like coupling term were also studied. An electrostatic-like coupling, in the absence of an applied field, can drive the ferroelectric layers toward 180° domains with very flat domain interfaces mainly due to the competition between this term and the dipole-dipole interaction. The antiferroelectric layers do not undergo an antiferroelectric-to-ferroelectric transition under the influence of an electrostatic-like coupling between layers as the ferroelectric layer splits into periodic domains at the expense of the domain wall energy. The long-range interactions become significant near the interfaces. For high periodicity structures with several interfaces, the interlayer long-range interactions substantially impact the configuration of the ferroelectric layers while the antiferroelectric layers remain quite stable unless these layers are near the Neel temperature. In systems investigated with several interfaces, the hysteresis loops do not exhibit a clear presence of antiferroelectricity that could be expected in the presence of anti-parallel dipoles, i.e., the switching takes place abruptly. Some recent experimental observations in ferroelectric-antiferroelectric multilayers are discussed where we conclude that the different electrical properties of bilayers and superlattices are not only due to strain effects alone but also due to long-range interactions. The latter manifests itself particularly in superlattices where layers are periodically exposed to each other at the interfaces.
采用蒙特卡罗方法模拟了由铁电 - 反铁电多层膜组成的二维伊辛晶格的相变和场驱动滞后演化，该模型考虑了长程偶极相互作用。对1 + 1双层和5 + 5超晶格进行了模拟。还研究了具有类静电耦合项的结构中各组分的相稳定性。在没有外场的情况下，类静电耦合主要由于该项与偶极 - 偶极相互作用之间的竞争，可驱使铁电层形成具有非常平坦畴界面的180°畴。由于铁电层以畴壁能量为代价分裂成周期性畴，反铁电层在层间类静电耦合的影响下不会发生反铁电 - 铁电转变。长程相互作用在界面附近变得显著。对于具有多个界面的高周期性结构，层间长程相互作用对铁电层的构型有显著影响，而反铁电层除非接近尼尔温度，否则保持相当稳定。在研究的具有多个界面的系统中，滞后回线并未表现出在存在反平行偶极时预期的明显反铁电现象，即切换是突然发生的。讨论了铁电 - 反铁电多层膜中最近的一些实验观察结果，我们得出结论，双层和超晶格的不同电学性质不仅归因于应变效应，还归因于长程相互作用。后者尤其在超晶格中表现明显，其中各层在界面处周期性地相互接触。
