Spontaneous Polarization in an Ultrathin Improper-Ferroelectric/Dielectric Bilayer in a Capacitor Structure at Cryogenic Temperatures

• DOI: 10.1103/physrevapplied.18.034071
• Publication Date: 2022-09-26T17:03:19Z
• Authors: Yu Yun; Pratyush Buragohain; Arashdeep Singh T...; Yuewei Yin; Xin Li; Xuanyuan Jiang; Rohan Mishra; Alexei Gruverman; Xiaoshan Xu
• Keywords: Dielectric response

To determine the effect of depolarization and critical thickness in improper-ferroelectric hexagonal-ferrite thin films, we investigate polarization switching a ferroelectric/dielectric bilayer capacitor structures at 20 K. Experimentally, show that spontaneous persists throughout studied range (3 to 80 unit cell), even with thick (10-nm) dielectric layer, suggesting no practical limit for applications. By fitting using phenomenological theory, remains finite when ferroelectric layer approaches zero, providing hint absence thickness. We also find interfacial effects multidomain formation govern mechanisms.