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Title: Mechanism of multi-defect induced ferromagnetism in undoped rutile TiO{sub 2}

Based on first-principles calculations, the coexistence of Ti vacancies (V{sub Ti}) and O vacancies (V{sub O}) is first considered to study the origin of the ferromagnetic ordering in undoped rutile TiO{sub 2}. The calculations show that V{sub O} can induce local magnetic moments in TiO{sub 2}, however, the ferromagnetic (FM) exchange interaction of two V{sub O} is not strong enough to induce room-temperature (RT) ferromagnetism on their own in undoped TiO{sub 2}. The FM coupling between two V{sub Ti} is about four times stronger than that between two V{sub O}. More importantly, the FM coupling between two V{sub Ti} is further enhanced after V{sub O} is introduced. Our results indicate that the electrons induced by V{sub O} mediate the long-range FM exchange interaction between two distant V{sub Ti}. This maybe the ferromagnetism mechanism in undoped TiO{sub 2}: V{sub Ti} produce local moments while the electrons induced by V{sub O} mediated the long-range FM exchange interaction. The results are in excellent agreement with the experimental evidences that V{sub O} alone cannot induce RT ferromagnetism while V{sub O} can promote the ferromagnetic ordering in undoped TiO{sub 2}.
Authors:
;  [1] ;  [2]
  1. College of Mathematics, Physics and Information Science, Zhejiang Ocean University, Zhoushan 316000 (China)
  2. State Key Laboratory of Superhard Materials and Department of Physics, Jilin University, Changchun 130012 (China)
Publication Date:
OSTI Identifier:
22304016
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 23; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COMPUTERIZED SIMULATION; COUPLING; CRYSTAL DEFECTS; EXCHANGE INTERACTIONS; FERROMAGNETISM; MAGNETIC MOMENTS; OXYGEN; RUTILE; TEMPERATURE RANGE 0273-0400 K; TITANIUM; TITANIUM OXIDES; VACANCIES