Doping Effect on Interlocked Ferroelectric and Structural Antiphase Domains in YMnO3

• Published in: Jpn J Appl Phys 2012-09, Vol.51 (9), p.09LE09-09LE09-4
• Main Authors: Kobayashi, Keisuke, Koyama, Tsukasa, Kamo, Hideki, Togawa, Yoshihiko, Horibe, Yoichi, Cheong, Sang Wook, Mori, Shigeo
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.51.09LE09

Changes in ferroelectric and structural antiphase domain structure by the partial substitution of nonmagnetic Ti 4+ ions at the Mn site were investigated carefully by electron diffraction, dark-field imaging, and high-resolution lattice imaging experiments. The ferroelectric and structural antiphase domains are revealed to be mutually interlocked in YMnO 3 and, on the other hand, when $x$ was increased up to $x\sim 0.30$ in YMn 1-x Ti x O 3 , the ferroelectric domains disappeared and the size of the structural antiphase domains decreased to approximately 10 nm at $x\sim 0.30$. High-resolution lattice images clearly demonstrate the coexisting state of nanodomains characterized by the modulated structure due to the structural trimerization and the nonmodulated structures. Our experimental results suggest that a partial substitution of Ti 4+ ions suppressed the ferroelectric displacement along the [001] direction and the correlation length of the Mn 3+ trimerization decreased.