Size-controlled synthesis of high-coercivity nanocrystals for data storage applications: The case of CoFe2O4

I&EC 36

O. Perales-Perez, oscar@ge.uprm.edu1, Yarilin Cedeņo-Mattei, yarilyn_@hotmail.com2, Eric Calderon, mcd25pr@yahoo.com2, Carlos Rinaldi3, Felix R. Roman, roman_felix@yahoo.com4, and Maharaj Tomar, mtomar@uprm.edu5. (1) Department of General Engineering-Materials Science and Engineering, University of Puerto Rico, Mayaguez, PR 00681-9000, (2) Department of Chemistry, University of Puerto Rico at Mayaguez, Mayaguez, PR 00680-9044, Mayaguez, PR 00680, (3) Chemical Enginnering, University of Puerto Rico at Mayaguez, Mayaguez, PR 00681, (4) Department of Chemistry, University of Puerto Rico, Mayaguez, PR 00681-9000, (5) Department of Physics, University of Puerto Rico at Mayaguez, Mayaguez, PR 00680-9044, Mayaguez, PR 00680
Among the various high-coercivity ferrite materials, cobalt ferrite (CoFe2O4) is well known to possess excellent chemical stability and good mechanical hardness. Furthermore, the large positive first order crystalline anisotropy constant exhibited by this ferrite made it a promising candidate for magneto-optical recording media. Applications of CoFe2O4 are often limited due to the lack of a synthesis technique capable to achieve a suitable control over particle size and size distribution. The control of crystal diameters within the superparamagnetic and single domain limits becomes indispensable to attain high room-temperature coercivity and moderate magnetization at the nanoscale. On that basis, the effect of reaction time under flow-rate controlled addition of reactants during the ferrite synthesis in aqueous phase was evaluated. The structural and magnetic characterization of ferrite nanocrystals produced in presence of pre-existent nuclei (`seeding/re-seeding assisted synthesisx) and followed by a size-sensitive particle separation will be also presented.
 

Poster Session
8:00 PM-10:00 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Sci-Mix

Division of Industrial & Engineering Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006