title: Metastability of free cobalt and iron clusters: a possible precursor to bulk ferromagnetism.
abstract: Homonuclear cobalt and iron clusters Co(N) and Fe(N) measured in a cryogenic molecular beam exist in two states with distinct magnetic moments (μ), polarizabilities, and ionization potentials, indicating distinct valences. The μ is approximately quantized: μ(N)∼2Nμ(B) in the ground states and μ(N)(*)∼Nμ(B) in the excited states for Co; μ(N)∼3Nμ(B) and μ(N)(*)∼Nμ(B) for Fe. At a large size, the average μ of the two states converges to the bulk value with diminishing ionization potential differences. The experiments suggest localized ferromagnetism in the two states and that itinerant ferromagnetism emerges from their superposition.
authors.affiliation: School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
authors.forename: Xiaoshan
authors.initials: X
authors.lastname: Xu
authors.forename: Shuangye
authors.initials: S
authors.lastname: Yin
authors.forename: Ramiro
authors.initials: R
authors.lastname: Moro
authors.forename: Anthony
authors.initials: A
authors.lastname: Liang
authors.forename: John
authors.initials: J
authors.lastname: Bowlan
authors.forename: Walt A
authors.initials: WA
authors.lastname: de Heer