IFLP   13074
INSTITUTO DE FISICA LA PLATA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Dopant local structure and magnetic behavior of Fe-doped TiO2 anatase nanoparticles
Autor/es:
C. RODRÍGUEZ TORRES; A. F. CABRERA; L. ERRICO; C. ADAN; F. G. REQUEJO; M. WEISSMAN; S. J. STEWART
Lugar:
LNLS, Campinas, Brasil.
Reunión:
Congreso; XVIII Reunión Anual de Usuarios del LNLS; 2008
Institución organizadora:
LNLS
Resumen:
<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0pc; margin-bottom:.0001pt; line-height:normal; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; color:windowtext; mso-ansi-language:EN-GB; mso-fareast-language:ES;} p {mso-margin-top-alt:auto; margin-right:0pc; mso-margin-bottom-alt:auto; margin-left:0pc; line-height:150%; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; color:black; mso-ansi-language:ES-AR; mso-fareast-language:ES-AR;} @page Section1 {size:51.0pc 66.0pc; margin:6.0pc 7.5pc 6.0pc 7.5pc; mso-header-margin:3.0pc; mso-footer-margin:3.0pc; mso-paper-source:0;} div.Section1 {page:Section1;} --> We present an investigation of Fe-doped TiO2 anatase nanoparticles (2.8 and 5.4 at.% Fe) where Fe substitutes Ti atoms without the presence of other phases. In order to characterize these samples we used x-ray absorption experiments, 57Fe Mössbauer spectroscopy, ab initio calculations and magnetometry. Results from iron K-edge near-edge and extended X-ray absorption fine structure confirm that Fe(III) replaces Ti(IV) in the TiO2 anatase structure increasing the metal-anion bond length. Mössbauer spectra recorded at room temperature show asymmetric Fe3+ broad doublets. These results agree with structural, hyperfine and magnetic properties calculated using density-functional theory if oxygen vacancies are present in the iron-oxygen octahedra. Mössbauer and magnetic measurements indicate that samples are paramagnetic at room temperature. At low temperatures, two kind of magnetic species can be distinguished: i) isolated paramagnetic Fe3+ ions and ii) antiferromagnetically coupled Fe3+ ions. These results also show that substitutional Fe in nanosized anatase TiO2 does not induce ferromagnetic ordering.
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