AVS 54th International Symposium | |
Understanding Biointerphases and Magnetism with Neutrons Topical Conference | Tuesday Sessions |
Session NT-TuA |
Session: | Magnetism |
Presenter: | A. Wiedenmann, Hahn-Meitner-Institut Berlin, Germany |
Correspondent: | Click to Email |
Small Angle Neutron Scattering (SANS) allows fluctuations of density, composition and magnetization to be analysed simultaneously on a nanometers length scale. This non-destructive technique was used to characterise magnetic colloids which are of growing interest for advanced medical applications. Such "Ferrofluids" consist of nanosized magnetic particles coated by nonmagnetic organic surfactants and dispersed in carrier liquids. Isotope contrast variation combined with the newly developed technique of polarised neutrons ("SANSPOL") allowed size distributions, compositions and magnetic moments of magnetic core-shell particles and magnetic aggregates to be evaluated precisely beside non-magnetic micelles of similar sizes.1 In concentrated Ferrofluids an unconventional pseudo-crystalline ordering has been monitored by SANS resulting from strong field-induced inter-particle correlations.2-3 New stroboscopic techniques have been developed which allowed the dynamics of ordering and realxation to be studied in a time range similar to that of X-ray photon-correlation spectroscopy.4
1Wiedenmann, A., Kammel, M., Heinemann, A., Keiderling, U. J. Phys. : Condensed Matter: 18 (2006) S2713-2736
2Wiedenmann, A., Hoell, A., Kammel, M. , Boesecke, P. Phys Rev. E 68 (2003) 031203
3Klokkenburg, M., Erné, B. H., Meeldijk, J.D., Wiedenmann, A., Pethukov, A.V., Philipse, A.P, Physical Revue Letters 97, 185702 (2006)
4Wiedenmann, A., Keiderling, U., Habicht, K., Russina, M., Gähler, R., Physical Review Letters 97, 057202 (2006)