Ferromagnetic stability optimization via oxygen- vacancy control in single- atom Co/TiO2 nanostructures

• 成果类型: Article
• 署名作者: Paidi, Vinod K.; Lee, Byoung-Hoon; Lee, Alex Taekyung; Ismail-Beigi, Sohrab; Grishaeva, Elizaveta; Vasala, Sami; Glatzel, Pieter; Ko, Wonjae; Ahn, Docheon; Hyeon, Taeghwan; Kim, Younghak; Lee, Kug-Seung
• 署名单位: European Synchrotron Radiation Facility (ESRF); Korea University; Yale University; Institute for Basic Science - Korea (IBS); Seoul National University (SNU); Pohang University of Science & Technology (POSTECH)
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-11104
• DOI: 10.1073/pnas.2409397121
• 发表日期: 2024-11-26
• 关键词: x-ray-absorption; titanium; tio2; spectroscopy; surface; ce3+

摘要

Oxygen vacancies and their correlation with the nanomagnetism and electronic structure are crucial for applications in dilute magnetic semiconductors design applications. Here, we report on cobalt single atom-incorporated titanium dioxide (TiO2) monodispersed nanoparticles synthesized using a thermodynamic redistribution strategy. Using advanced synchrotron-based X-ray techniques and simulations, we find trivalent titanium is absent, indicating trivalent cations do not influence ferromagnetic (FM) stability. Density functional theory calculations show that the FM stability between Co2+ ions is very weak. However, electron doping from additional oxygen vacancies can significantly enhance this FM stability, which explains the observed room-temperature ferromagnetism. Moreover, our calculations illustrate enhanced FM interactions between Co-Ti + V-O complexes with additional oxygen vacancies. This study explores the electronic structure and room-temperature ferromagnetism using monodispersed nanocrystallites with single-atom-incorporated TiO2 nanostructures. The strategies described herein offer promise in revealing magnetism in other single-atom-incorporated nanostructures.