resumo
CoFe2O4-TiO2 and CoFe2O4-ZnO nanoparticles/film composites were prepared from directed assembly of colloidal CoFe2O4 in a Langmuir-Blodgett monolayer and atomic layer deposition (ALD) of an oxide (TiO2 or ZnO). The combination of these two methods permits the use of well-defined nanoparticles from colloidal chemistry, their assembly on a Urge scale, and the control over the interface between a ferrimagnetic material (CoFe2O4) and a semiconductor (TiO2 or ZnO). Using this approach, architectures can be assembled with a precise control from the Angstrom scale (ALD) to the micrometer scale (Langmuir-Blodgett film). The resulting heterostructures present well-calibrated thicknesses, Electron microscopy and magnetic measurement studies give evidence that the size of the nanoparticles and their intrinsic magnetic properties are not altered by the various steps involved in the synthesis process. Therefore, the approach is suitable to obtain a layered composite with a quasi-monodisperse layer of ferrimagnetic nanoparticles embedded in an ultrathin film of semiconducting material.
palavras-chave
COBALT FERRITE NANOPARTICLES; LANGMUIR-BLODGETT TECHNIQUE; MAGNETIC-PROPERTIES; SOL-GEL; MONODISPERSE NANOCRYSTALS; THERMAL-DECOMPOSITION; SURFACE MODIFICATION; OXIDE NANOCRYSTALS; FINE PARTICLES; SIZE
categoria
Chemistry; Materials Science
autores
Clavel, G; Marichy, C; Willinger, MG; Ravaine, S; Zitoun, D; Pinna, N
nossos autores
Nicola Pinna
InvestigadorGrupos
Projectos
Functionalised Advanced Materials and Engineering of Hybrids and Ceramics - FAME (FAME)
Structural and chemical characterization at the nanometer scale (PTDC/CTM/100468/2008)
RMNE-UA-National Network of Electron Microscopy (REDE/1509/RME/2005 )
agradecimentos
Dr. Mato Knez and Seung-Mo Lee from the Max Planck Institute of Microstructure Physics in Halle (Germany) are acknowledged for the ALD of ZnO, and Dr. Andrei Kholkin and Dr. Dmitry Karpinsky are acknowledged for AFM measurements. This work was partially supported by the WCU (World Class University) program through the National Research Foundation (NRF) of Korea funded by the Ministry of Education, Science and Technology (R31-10013), the network of excellence FAME, FCT projects (PTDC/CTM/65667/2006), (PTDC/CTM/100468/2008), RNME - Pole University of Aveiro, FCT project REDE/1509/RME/2005, and FCT grant no. (SFRH/BD/28848/2006).