Magnetic Nanoparticles: Gas Phase Preparation
Magnetic Nanoparticles are prepared utilizing an inert gas condensation process. Hereunto, a supersaturated vapour of the material of choice is sputtered from an alloy target at pressures of roughly pAgg = 1 mbar. Within this supersaturated metal vapour, particle nuclei are formed by homogeneous nucleation from the vapour. The nanoparticles then grow by successive aggregation and sintering. |
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We use a UHV system (type NanoDep60) provided by Oxford Applied Research, Inc. for this process. The particles are grown in the nucleation and aggregation chamber. From there, they are ejected into high vacuuum (pHV = 10-6 - 10-4 mbar) by means of differential pumping between two appertures, thereby providing a free particle beam. A quadrupole mass spectrometer (QMS) can be used to size-fractionate the effusing particles. Prior to their deposition onto appropriate substrates, the nanoparticles can be subjected to optical heating in a light furnace. |
Fig. 1: Schematic drawing of the experimental setup for gas phase based preparation of nanoparticles.
Fig. 2: Photograph of the nanoparticle deposition system NanoDep60 provided by Oxford Applied Reasearch, Inc.