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KR: Fachverband Kristallographie

KR 10: Poster: Multiferroics (with MA, DF, KR, DS)

KR 10.71: Poster

Dienstag, 23. März 2010, 10:45–13:45, Poster A

Magnetic properties of CoRh core shell nanoparticles — •Björn Münzing¹, Kai Fauth¹, Nabil Atamena², Diana Ciuculescu², and Catherine Amiens² — ¹Physikalisches Institut, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany — ²LCC Toulouse, 205 rte. de Narbonne, 31077 Toulouse Cedex 04, France

We present an X-ray magnetic circular dichroism (XMCD) study of the magnetic properties of Co@Rh core-shell-nanoparticles with a mean diameter of ≈ 1.8 nm, prepared by colloidal chemistry using organo-metallic precursors.

The local Co atomic magnetic moments in particles of different composition increase with increasing amount of Rh. This may be attributed to a decreasing influence of tetramethylpiperidine ligands on the 3d-metal when the particle surface is enriched with Rh. The magnetic response is essentially superparamagnetic (T ≥ 12 K) and magnetic saturation is not attained in applied fields of up to 3 T for all compositions. The measurement of the magnetic circular dichroism on Rhodium reveals the ferromagnetic coupling of Co and Rh in these particles.

Additionally we find striking differences in magnetic coupling between the particles at short inter particle distance. This could be attributed to an effective antiferromagnetic coupling once the particle surfaces are significantly enriched with Rh.