title: Nuclear spin driven quantum relaxation in LiY0.998Ho0.002F4.
abstract: Staircaselike hysteresis loops of the magnetization of a LiY0.998Ho0.002F4 single crystal are observed at subkelvin temperatures and low field sweep rates. This behavior results from quantum dynamics at avoided level crossings of the energy spectrum of single Ho3+ ions in the presence of hyperfine interactions. Enhanced quantum relaxation in constant transverse fields allows the study of the relative magnitude of tunnel splittings. At faster sweep rates, nonequilibrated spin-phonon and spin-spin transitions, mediated by weak dipolar interactions, lead to magnetization oscillations and additional steps.
authors.affiliation: Laboratoire de Magnétisme Louis Néel, CNRS, BP166, 38042 Grenoble Cedex-09, France.
authors.forename: R
authors.initials: R
authors.lastname: Giraud
authors.forename: W
authors.initials: W
authors.lastname: Wernsdorfer
authors.forename: A M
authors.initials: AM
authors.lastname: Tkachuk
authors.forename: D
authors.initials: D
authors.lastname: Mailly
authors.forename: B
authors.initials: B
authors.lastname: Barbara