title: Quantum dynamics of atomic magnets: cotunneling and dipolar-biased tunneling.
abstract: Multispin tunneling cross relaxations in an ensemble of weakly coupled Ho3+ ions, mediated by weak anisotropic dipolar interactions, can be evidenced by ac-susceptibility measurements in a high temperature regime. Based on a four-body representation, including the rare-earth nuclear spin, two-ion tunneling mechanisms can be attributed to both dipolar-biased tunneling and cotunneling processes. The coreversal involving entangled pairs of magnetic moments is discussed with a particular emphasis, giving new evidence to elucidate the many-body quantum dynamics in dipolar spin glasses.
authors.affiliation: Laboratoire de Magnétisme Louis Néel, CNRS, BP 166, 38042 Grenoble CEDEX-09, France.
authors.forename: R
authors.initials: R
authors.lastname: Giraud
authors.forename: A M
authors.initials: AM
authors.lastname: Tkachuk
authors.forename: B
authors.initials: B
authors.lastname: Barbara