[1C01-10] Thin Film (TF)

3:45 PM - 4:00 PM JST(6:45 AM - 7:00 AM UTC)

[1C05] Fluorination effects on the ferroelectric and magnetic properties of Ba–substituted BiFeO₃ thin films studied by X–ray spectroscopy

*Akiko Kamigaito¹, Kei Shigematsu², Masaki Kobayashi³, Kenta Amemiya⁴, Hiroshi Kumigashira⁵, Tsukasa Katayama⁶, Akira Chikamatsu¹ (1. Department of Chemistry, Faculty of Science, Ochanomizu University (Japan), 2. Materials and Structures Laboratory, Institute of Integrated Research, Institute of Science Tokyo (Japan), 3. Center for Spintronics Research Network, The University of Tokyo (Japan), 4. Institute of Materials Structure Science, High Energy Accelerator Research Organization (Japan), 5. Institute of Multidisciplinary Research for Advanced Materials, Tohoku University (Japan), 6. Department of Applied Chemistry, Faculty of Science Division I, Tokyo University of Science (Japan))

Multiferroic materials, which exhibit both ferroelectricity and magnetic ordering, are promising for low-power devices. BiFeO₃ is a representative material, but its R3c structure causes complex ferroelectric switching. Ba²⁺ substitution can induce tetragonal distortion and stabilize a simpler P4mm structure; however, the accompanying oxygen vacancies may suppress the stereochemical activity of Bi³⁺ lone pairs and degrade ferroelectricity. In this study, Bi_0.8Ba_0.2FeO_2.9 and Bi_0.8Ba_0.2FeO_2.8F_0.2 epitaxial thin films were prepared to clarify the effects of Ba and F codoping. X-ray magnetic circular dichroism measurements revealed that fluorination does not significantly alter the Fe magnetic sites. In contrast, ferroelectricity was observed only in Bi_0.8Ba_0.2FeO_2.8F_0.2. These results suggest that fluorination restores the stereochemical activity of Bi³⁺ lone pairs by compensating anion vacancies, making F incorporation an effective strategy for tuning ns²-type multiferroic oxides.

Password required to view