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Self-organized Co/Pt nanoparticulate arrays offer a novel approach to fabricating magnetic recording media with the potential for supporting Terabit/in.2 recording densities. Protein-derived Co/Pt nanoparticles are prepared within apoferritin from aqueous reactants, with synthesis conditions controlling grain size, structure, and composition. Smooth films on glass disk substrates are produced by either spin coating or dip coating from aqueous dispersions of the precursor material. Films are typically annealed at 590 °C for 60 min with a 19 kPa (190 mBar) partial pressure of H2 to form the L10 phase. By varying the annealing conditions we are able to produce coercivities in the range of 500–8000 Oe. Electrical testing of Co/Pt nanoparticulate media using a contact test recorder shows that these nanoparticle films are capable of sustaining recording densities of more than 12.6 Gbits/in.2 (143.6 kfci, kilo flux changes per inch). In this article we will present results from finished films with regard to film structure, magnetic properties, and recording capabilities.

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Lanthanide surfactants of the type Ln(AOT)3 have been prepared and characterized, where Ln = Tb, Eu, Nd, and AOT is bis(2-ethylhexyl) sulfosuccinate. Small-angle neutron scattering experiments indicate that spherical reverse micelles form in cyclohexane. The luminescence lifetimes of lanthanide ions held inside these aggregates were found to depend on the molar ratio w = [water]/[AOT-]. This behavior is consistent with changes in the Ln3+ solvation:  in “dry” micelles the ions are complexed by the surfactant polar groups, while addition of water results in progressive Ln ion hydration. The results show that reversed micelles can be used to control photophysical properties of lanthanides.