Downward self-polarization of lead-free (K_0.5Na_0.5)(Mn_0.005Nb_0.995)O₃ ferroelectric thin films on Nb:SrTiO₃ substrate

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• 作者：Hae Jin Seog ; Chang Won Ahn ; Shinuk Cho ; Kwang-Eun Kim ; Chan-Ho Yang ; Tae Yeong Koo ; Sun-Young Lee ; Jong Pil Kim and Ill Won Kim
• 刊名：physica status solidi (RRL) - Rapid Research Letters
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：11
• 期：1
• 全文大小：406K
• ISSN：1862-6270

文摘

Spontaneously appearing macroscopic polarization (self-polarization) in ferroelectrics without an electrode or an external electric field would enable the freedom to design many ferroelectric heterostructures and devices. The (K_0.5Na_0.5)(Mn_0.005Nb_0.995)O₃ (KNMN) thin film was grown on Nb:SrTiO₃ single-crystal substrate and the resultant self-polarization behavior due to strain relaxation was investigated. The lattice mismatch and difference in TEC between the KNMN thin film and the Nb:SrTiO₃ substrate creates a compressive strain. The compressive strain gradient may be the main cause for the observed downward self-polarization. The downward self-polarization of the KNMN thin film can be explained by the strong inhomogeneous compressive strain caused by strain relaxation. (