Spin fluctuations of paramagnetic Rh clusters revealed by X-ray magnetic circular dichroism

Vitoria Barthem (1) , Andrei Rogalev (2) , Fabrice Wilhelm (2) , M.M. Sant'Anna (1) , S.L.A. Mello (1) , Yuepeng Zhang (3) , Pascale Bayle-Guillemaud (4, 5) , Dominique Givord (3) , Nora Dempsey (3)

1 IF / UFRJ - Instituto de Física da Universidade Federal do Rio de Janeiro
2 ESRF - European Synchrotron Radiation Facility
3 NEEL - MNM - Micro et NanoMagnétisme
4 LEMMA - Laboratoire d'Etude des Matériaux par Microscopie Avancée
5 SP2M - UMR 9002 - Service de Physique des Matériaux et Microstructures

The magnetic moment induced on Rh atoms, forming 1.6 nm average diameter clusters, embedded in an Al2O3 matrix, has been determined using x-ray magnetic circular dichroism measurements. The magnetic moment varies linearly with the applied magnetic field. At 2.3 K and under 17 T, the spin magnetic moment amounts to 0:067ð2Þ B=Rh atom. The orbital moment does not exceed 2% of the spin moment. The susceptibility is highly temperature dependent. This is in agreement with a prediction due to Moriya and Kawabata, that in itinerant electron systems, close to the onset of magnetism, the renormalization of the magnetic susceptibility by electron correlations, leads to a Curie-like behavior.

Mots clés: Moryia spin fluctuations; Pauli paramagnetism; Rh clusters

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Vitoria Barthem, Andrei Rogalev, Fabrice Wilhelm, M.M. Sant'Anna, S.L.A. Mello, et al.. Spin fluctuations of paramagnetic Rh clusters revealed by X-ray magnetic circular dichroism. Physical Review Letters, 2012, 109, pp.197204. ⟨10.1103/PhysRevLett.109.197204⟩. ⟨hal-00969046⟩