title: Direct experimental evidence for atomic tunneling of europium in crystalline Eu8Ga16Ge30.
abstract: Mössbauer-effect and microwave absorption experimental evidence unambiguously demonstrates the presence of slow, approximately 450 MHz, tunneling of magnetic europium between four equivalent sites in Eu8Ga16Ge30, a stoichiometric clathrate. Remarkably, six of the eight europium atoms, or 11% of the constituents in this solid, tunnel between these four sites separated by 0.55 A. The off centering of the atoms or ions in crystalline clathrates appears to be a promising route for producing Rabi oscillators in solid-state materials.
authors.affiliation: Department of Materials Science and Engineering, The University of Tennessee, Knoxville, Tennessee 37996-2200, USA.
authors.forename: Raphaël P
authors.initials: RP
authors.lastname: Hermann
authors.forename: Veerle
authors.initials: V
authors.lastname: Keppens
authors.forename: Pierre
authors.initials: P
authors.lastname: Bonville
authors.forename: George S
authors.initials: GS
authors.lastname: Nolas
authors.forename: Fernande
authors.initials: F
authors.lastname: Grandjean
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Long
authors.forename: Hans M
authors.initials: HM
authors.lastname: Christen
authors.forename: Bryan C
authors.initials: BC
authors.lastname: Chakoumakos
authors.forename: Brian C
authors.initials: BC
authors.lastname: Sales
authors.forename: David
authors.initials: D
authors.lastname: Mandrus