Nonlinear Optical Imaging of Entangled Heterophase Polydomains in Ferroelectric BZT Films

Abstract Quantitative evaluation of multi‐phase evolution and domain characteristics in ferroelectric thin films is essential for understanding device engineering and underlying physical mechanisms. However, extracting local strain distribution and defects remains challenging with conventional techn...

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Bibliographic Details
Main Authors: Piyali Maity, Hongbo Chen, Jun Ouyang, Yuhang Ren
Format: Article
Language:English
Published: Wiley-VCH 2025-08-01
Series:Advanced Electronic Materials
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Online Access:https://doi.org/10.1002/aelm.202500278
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Summary:Abstract Quantitative evaluation of multi‐phase evolution and domain characteristics in ferroelectric thin films is essential for understanding device engineering and underlying physical mechanisms. However, extracting local strain distribution and defects remains challenging with conventional techniques. Here, the azimuth‐ and polarization‐dependent second harmonic generation (SHG) approach for distinguishing the tetragonal and rhombohedral domain variants in ferroelectric BaZr0.2Ti0.8O3 (BZT) films is presented. It is demonstrated that strain from the LaAlO3 (LAO) substrates breaks the in‐plane symmetry of BZT thin films, significantly altering their second‐order nonlinear susceptibility. Variations in SHG intensity and susceptibility characterize and spatially map polymorphic nanodomains and internal elastic strain fields within the BZT/LAO heterostructure. It is shown that the competition between tetragonal and rhombohedral phases gives rise to anisotropic nanodomains with complex elastic and electric fields. The SHG imaging spectroscopy is well‐suited for understanding microstructural variations in ferroelectrics, which are directly relevant to device performance in memory and energy storage applications.
ISSN:2199-160X