Role of Ti 3d carriers in mediating the ferromagnetism of Coâ¶TiO2 anatase thin films.
Phys Rev Lett
; 106(4): 047602, 2011 Jan 28.
Article
em En
| MEDLINE
| ID: mdl-21405362
ABSTRACT
We study the surface and bulk electronic structure of the room-temperature ferromagnet Coâ¶TiO(2) anatase films using soft- and hard-x-ray photoemission spectroscopy with probe sensitivities of â¼1 and â¼10 nm, respectively. We obtain direct evidence of metallic Ti(3+) states in the bulk, which get suppressed to give a surface semiconductor, thus indicating the difference in electronic structure between surface and bulk. X-ray absorption and resonant photoemission spectroscopy reveal Ti(3+) electrons at the Fermi level (E(F)) and high-spin Co(2+) electrons occurring away from E(F). The results show the importance of the charge neutrality condition Co(2+)+V(O)(2-)+2Ti(4+)âCo(2+)+2Ti(3+) (V(O) is oxygen vacancy), which gives rise to the elusive Ti 3d carriers mediating ferromagnetism via the Co 3d-O 2p-Ti 3d exchange interaction pathway of the occupied orbitals.
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MEDLINE
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En
Ano de publicação:
2011
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Article