Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)
MA 20.86: Poster
Dienstag, 28. März 2006, 15:15–19:15, P1
FePt nanoparticles from a Haberland type gas aggregation source: Morphological and structural characterization — •Franziska Schäffel, Elias Mohn, Thomas Gemming, Bernd Rellinghaus, and Ludwig Schultz — IFW Dresden, P.O. Box 270116, D-01171 Dresden
FePt nanoparticles are synthesized from a gas aggregation source of the type designed by H. Haberland [1]. The particles grow from a supersaturated metal vapor provided by sputtering from an alloy target at pressures of roughly p = 1 mbar. After nucleation and growth of the particles within an aggregation volume, they are ejected via ultrasonic expansion through an orifice into high vacuum (10−4 mbar≥ p≥ 10−5 mbar). As a consequence and in contrast to other gas phase techniques [2], further agglomeration of the particles is suppressed. Size fractionation of the particles can be obtained by using a quadrupole mass spectrometer for masses as high as 4× 106 amu [3]. The morphology and crystal structure of the particles were investigated by means of conventional and high resolution transmission electron microscopy. The effect of the gas pressure in the aggregation chamber, the aggregation volume, the gas type, the orifice size, and the sputtering power on particle size, particle morphology, and particle size distribution was investigated. The system parameters were optimized to obtain non-agglomerated particles with diameters of dP ≃ 5 nm, spherical morphology, and a narrow particle size distribution.
[1] “NC200U Nanocluster source application note”, Oxford Applied Research Ltd., UK. [2] S. Stappert et al., J. Cryst. Growth 252 (2003) 440. [3] S.H. Baker et al., Rev. Sci. Inst. 68 (1997) 1853.