title: Lattice size induced moment formation on isolated Fe atoms in nanocrystalline Nb.
abstract: Measurements of the local susceptibility and 3d spin relaxation rate for single Fe impurities embedded in a nanocrystalline Nb host indicates the emergence of a local moment on Fe at and below a critical size of 11 nm. Our ab initio electronic structure calculations show that the moment formation occurs due to Stoner enhancement arising from a size dependent lattice expansion and a consequent shift in the Fermi level. We also show that a size-induced positive host spin polarization of the Nb-4d band electrons strongly influences the fluctuation rate of the Fe moment.
authors.affiliation: Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai-400005, India.
authors.forename: S N
authors.initials: SN
authors.lastname: Mishra
authors.forename: S K
authors.initials: SK
authors.lastname: Mohanta
authors.forename: S M
authors.initials: SM
authors.lastname: Davane
authors.forename: N
authors.initials: N
authors.lastname: Kulkarni
authors.forename: Pushan
authors.initials: P
authors.lastname: Ayyub