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MA: Magnetismus

MA 31: Magnetische Partikel/Cluster II

MA 31.2: Talk

Wednesday, March 9, 2005, 11:15–11:30, TU H1012

Magnetic properties of Ni/Ni-oxide core-shell — •V. Schneider¹, A. Tillmanns², A. Reinholdt¹, T. Weirich³, and U. Kreibig¹ — ¹I. Phys. Inst. I.a, RWTH Aachen, Postfach 52056 — ²II. Phys. Inst. II.a, RWTH Aachen, Hüskensweg, 52074 Aachen — ³GFE, RWTH Aachen, Ahormstr. 55, 52074 Aachen

Nickel/Nickel-oxide core-shell nanoparticles are, at present, of great interest concerning medical applications and data storage devices.

Nanoparticles were produced by laser evaporation and adiabatic expansion. They were deposited on substrates and subsequently oxidized in-situ at a temperature up to 400^∘C forming oxide shells.

This talk will present structural and magnetic analysis on those particles including detailed Energy Filtered Transmission Electron Microscopy (EFTEM) and High Resolution Transmission Electron Microscopy (HRTEM). Magnetic hysteresis measurements were performed by SQUID. Results of samples with three different states of oxidation are discussed and their hysteresis including the observed exchange bias are interpreted.