title: Absence of exchange interaction between localized magnetic moments and conduction-electrons in magnetic ions diluted in Ag-nanoparticles.
abstract: The Electron Spin Resonance (ESR) of diluted magnetic ions (MI) of Er3+, Yb3+ and Mn2+ in Ag nanoparticles (NPs) is reported. Monodisperse samples of Ag NPs doped with these MI were synthesized by reducing silver nitrate and MI-oxides. This simple method can be extended to all rare-earths. The measurements of the g-values and hyperfine splittings indicates that the MI are located at cubic sites in the Ag:MI NPs. The ESR spectra show that there is no g-shift and Korringa-relaxation due to the exchange interaction between the MI and the conduction electrons, suggesting that the exchange interaction is absent in the Ag:MI NPs. Thus, the nature of this interaction needs to be reexamined at the nanoscale range.
authors: Instituto de Física Gleb Wataghin, UNICAMP, Campinas-SP 13083-970, Brazil.
authors: J M
authors: JM
authors: Vargas
authors: W
authors: W
authors: Iwamoto
authors: L M
authors: LM
authors: Holanda
authors: S B
authors: SB
authors: Oseroff
authors: P G
authors: PG
authors: Pagliuso
authors: C
authors: C
authors: Rettori
mesh_terms: D003102:Colloids / Q000737:chemistry*; D004553:Electric Conductivity; D008280:Magnetics; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D012834:Silver / Q000737:chemistry*
chemical_list: D003102:Colloids; D012834:Silver