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Title: Strain-induced lead-free morphotropic phase boundary
Enhanced susceptibilities in ferroelectrics often arise near phase boundaries between competing ground states. While chemically-induced phase boundaries have enabled ultrahigh electrical and electromechanical responses in lead-based ferroelectrics, precise chemical tuning in lead-free alternatives, such as (K,Na)NbO3 thin films, remains challenging due to the high volatility of alkali metals. Here, we demonstrate strain-induced morphotropic phase boundary-like polymorphic nanodomain structures in chemically simple, lead-free, epitaxial NaNbO3 thin films. Combining ab initio simulations, thin-film epitaxy, scanning probe microscopy, synchrotron X-ray diffraction, and electron ptychography, we reveal a labyrinthine structure comprising coexisting monoclinic and bridging triclinic phases near a strain-induced phase boundary. The coexistence of energetically competing phases facilitates field-driven polarization rotation and phase transitions, giving rise to a multi-state polarization switching pathway and large enhancements in dielectric susceptibility and tunability across a broad frequency range. Our results open new possibilities for engineering lead-free thin films with enhanced functionalities for next-generation applications.  more » « less
Award ID(s):
2442399
PAR ID:
10657567
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more » ; ; ; ; ; ; ; « less
Publisher / Repository:
Springer Nature
Date Published:
Journal Name:
Nature Communications
Volume:
16
Issue:
1
ISSN:
2041-1723
Page Range / eLocation ID:
7766
Subject(s) / Keyword(s):
ferroelectrics thin films strain morphotropic phase boundary NaNbO3 complex oxides
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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