2004/07/16 by J. Daniel Bryan, Bryan, J. Daniel, Steve M. Heald +5
Materials Science · Physics and Astronomy · #Catalytic Processes in Materials Science #Copper-based nanomaterials and applications #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Quantum Dots Synthesis And Properties #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.cond-mat/0407451
To be published in the Journal of the American Chemical Society
arxiv created 2004/07/16 · openalex publication_date 2004/07/16 · arxiv updated 2009/12/01 · openalex created_date 2022/10/01 · openalex updated_date 2026/07/28
Colloidal cobalt-doped TiO2 (anatase) nanocrystals were synthesized and studied by electronic absorption, magnetic circular dichroism, transmission electron microscopy, magnetic susceptibility, cobalt K-shell X-ray absorption spectroscopy, and extended X-ray absorption fine structure measurements. The nanocrystals were paramagnetic when isolated by surface-passivating ligands, weakly ferromagnetic (Ms = 1.5 x 10-3 mB/Co2+ at 300 K) when aggregated, and strongly ferromagnetic (up to Ms = 1.9 mB/Co2+ at 300 K) when spin-coated into nanocrystalline films. X-ray absorption data reveal that cobalt is in the Co2+ oxidation state in all samples. In addition to providing strong experimental support for the existence of intrinsic ferromagnetism in cobalt-doped TiO2, these results demonstrate the possibility of using colloidal TiO2 diluted magnetic semiconductor nanocrystals as building blocks for assembly of ferromagnetic semiconductor nanostructures with potential spintronics applications.