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The magnetic and magnetoresistive properties of Ln(sub0.7)Pb(sub0.3)Mn(sub1-x)FexO(sub3) are reported. They were prepared using the sol-gel low temperature method which results in smaller grains, producing high purity and homogenous powders. The structural, magnetic, and magnetoresistance measurements were compared, to provide a better understanding of the effects due to the presence of different lanthanide elements and the substitution of Mn by Fe ions.

The article presents a complete magnetic, as well as structural characterization of the different thiol capped ferromagnetic Ag nanoparticles. The nanoparticles even with similar sizes are shown to exhibit different magnetic behaviors.

Different dodecanethiol capped Au nanoparticles (NP) with similar sizes (∼2 nm) but different ferromagnetic signals at room temperature have been investigated by means of x-ray absorption spectroscopy at the Au L3-edge. The reversion of the x-ray magnetic circular dichroism signal with the change of sign of the external applied magnetic field confirms the location of the magnetism at the Au atoms. In comparison with the Au foil, all the samples present accentuated white lines at the x-ray absorption near-edge structure (XANES) indicating generation of 5d holes in the Au atoms located at surface of the NPs as consequence of a localized charge transfer from the Au surface atoms to the S atoms of the capping agent. XANES spectra reflect differences among the electronic structure of the Au NPs which are compared with the observed different macroscopic magnetic signals. [ABSTRACT FROM AUTHOR]