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Prof. Dr. Luis Fernandez Barquin, Univ. Cantabria – Magnetic correlation lengths in ensembles of magnetic nanoparticles – 17 de Junho 14:00
17 de junho:14:00 - 15:00
In this talk I will review some recent results in different systems which have been selected depending on the nanoscopic correlation length of their magnetic coupling. First we will show large correlations are found magnetic nanoparticle of Fe oxide (magnetite/maghemite) produced by artificial (chemical) and natural (bacteria) routes. In the first ones a change of signal is observed at the Vewey temperature by Raman spectroscopy which is correlated to the values of the magnetic moment obtained from neutron diffraction experiments at D1B (ILL). In magnetotactic bacteria, variations of the moments in the magnetosomes (50 nm) reveled in SANS is discussed. Finally, we will analyse the correlation lengths present in nanoparticles of rare earth intermetallics of the RX2 (R = rare Earth, X = Cu) family. We will briefly comment on the magnetic ordering and dynamics (Mdc, Xac, ND, INS) of TbCu2,GdCu2 and NdCu2 alloys produced with controlled nanoparticle size (8-30 nm).