TY - JOUR
T1 - Role of Ti 3d carriers in mediating the ferromagnetism of CoTiO2 anatase thin films
AU - Ohtsuki, T.
AU - Chainani, A.
AU - Eguchi, R.
AU - Matsunami, M.
AU - Takata, Y.
AU - Taguchi, M.
AU - Nishino, Y.
AU - Tamasaku, K.
AU - Yabashi, M.
AU - Ishikawa, T.
AU - Oura, M.
AU - Senba, Y.
AU - Ohashi, H.
AU - Shin, S.
PY - 2011/1/25
Y1 - 2011/1/25
N2 - We study the surface and bulk electronic structure of the room-temperature ferromagnet CoTiO2 anatase films using soft- and hard-x-ray photoemission spectroscopy with probe sensitivities of ∼1 and ∼10nm, respectively. We obtain direct evidence of metallic Ti3+ 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 Ti3+ electrons at the Fermi level (EF) and high-spin Co2+ electrons occurring away from EF. The results show the importance of the charge neutrality condition: Co2++VO2-+2Ti4+ Co2++2Ti3+ (VO 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.
AB - We study the surface and bulk electronic structure of the room-temperature ferromagnet CoTiO2 anatase films using soft- and hard-x-ray photoemission spectroscopy with probe sensitivities of ∼1 and ∼10nm, respectively. We obtain direct evidence of metallic Ti3+ 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 Ti3+ electrons at the Fermi level (EF) and high-spin Co2+ electrons occurring away from EF. The results show the importance of the charge neutrality condition: Co2++VO2-+2Ti4+ Co2++2Ti3+ (VO 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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U2 - 10.1103/PhysRevLett.106.047602
DO - 10.1103/PhysRevLett.106.047602
M3 - Article
AN - SCOPUS:79251482461
VL - 106
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 4
M1 - 047602
ER -