Multilevel hysteresis loop engineered with ferroelectric nano-metamaterials

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• 作者：Le Van Lich^a ; ¹ ; ^{le.lich.68m@st.kyoto-u.ac.jp} ; Takahiro Shimada^a ; ¹ ; ^{shimada@me.kyoto-u.ac.jp} ; Shahmohammadi Sepideh^a ; Jie Wang^b ; Takayuki Kitamura^a
• 关键词：Multilevel hysteresis loop ; Multilevel polarization switching ; Ferroelectric nano-metamaterials ; Nanoporous ferroelectric structure ; Phase-field model
• 刊名：Acta Materialia
• 出版年：2017
• 出版时间：15 February 2017
• 年：2017
• 卷：125
• 期：Complete
• 页码：202-209
• 全文大小：3339 K
• 卷排序：125

文摘

Polarization switching in ferroelectric and multiferroic materials provides a means of designing a broad range of multifunctional devices. To date, such applications have typically exploited 180° ferroelectric polarization switching, where the polarization vector can be alternated between parallel or anti-parallel to the external electric field, i.e., bi-states. However, the coupling between the direction of switching and the long-range order parameter puts a limit on the well-defined polarization state, hindering the use of polarization switching and the advancement of novel applications. Using the ferroelectric nano-metamaterial concept, we demonstrate here that successive polarization switching through multiple well-defined stable states with a long-range order parameter decoupled from the direction of switching can be achieved, and consequently, controllable and multilevel hysteresis loops are obtained under a unidirectional electric field. The equilibrium polarization configuration of stable states are tailored by designing a nanoporous ferroelectric structure based on the ferroelectric nano-metamaterial concept. The orientation of the homogeneous electric field is then controlled to achieve the desired polarization switching behavior and hence the hysteresis loop level, which can pass through all stable polarization states. In addition, a general rule for the nanostructure-state-level of switching is established, from which a high level of hysteresis loop can be designed and achieved. The present study provides a foundation for novel devices based on multilevel ferroelectric switching, such as multilevel data storage memory, multi-logic gates, and electromechanical devices with multilevel control.