Intrinsic Ferromagnetism in Insulating Cobalt Doped Anatase TiO₂

Journal Article · Fri Apr 22 04:00:00 EDT 2005 · Physical Review Letters, 94(15):Art. No. 157204

DOI:https://doi.org/10.1103/PhysRevLett.94.157204· OSTI ID:15016795

Griffin, Kelli A; Pakhomov, Alexandre; Wang, Chong M; Heald, Steve M; Krishnan, Kannan M

Using complementary experiments we show that the room temperature ferromagnetism observed in anatase Co:TiO₂ films is not carrier mediated, but coexists with the dielectric state. TEM and x-ray absorption spectroscopy reveal a solid solution of Co in anatase, where Co is not metallic but in the +2 state substituting for Ti. Measurements at 300 K yield a Ms of 1.1 µB/Co atom, while all films are highly insulating. The evidence of intrinsic ferromagnetism in the dielectric ground state of Co:TiO₂ leads to new considerations for the origin of ferromagnetism in transition metal doped oxides.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 15016795
• Report Number(s): PNNL-SA-43211; 6910; 2487; KP1704020
• Journal Information: Physical Review Letters, 94(15):Art. No. 157204, Journal Name: Physical Review Letters, 94(15):Art. No. 157204 Journal Issue: 15 Vol. 94; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION SPECTROSCOPY
COBALT
DIELECTRIC MATERIALS
Environmental Molecular Sciences Laboratory
FERROMAGNETISM
GROUND STATES
ORIGIN
OXIDES
Room-temperature ferromagnetism
SOLID SOLUTIONS
TRANSITION ELEMENTS
diluted magnetic semiconductor
epitaxial-growth
exchange
films