title: Distribution of tunnel splittings in Mn(12) acetate.
abstract: In magnetic fields applied parallel to the anisotropy axis, the relaxation of the magnetization of Mn(12)-acetate measured for different sweep rates collapses onto a single scaled curve. The form of the scaling implies that the dominant symmetry-breaking process responsible for tunneling is a locally varying second-order transverse anisotropy, forbidden by tetragonal symmetry in the perfect crystal, which gives rise to a broad distribution of tunnel splittings in a real crystal of Mn(12) acetate. Different forms applied to even- and odd-numbered steps provide a clear distinction between even resonances (associated with crystal anisotropy) and odd resonances (which require a transverse magnetic field).
authors.affiliation: Physics Department, City College of the City University of New York, New York, New York 10031, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Mertes
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.forename: M P
authors.initials: MP
authors.lastname: Sarachik
authors.forename: Y
authors.initials: Y
authors.lastname: Paltiel
authors.forename: H
authors.initials: H
authors.lastname: Shtrikman
authors.forename: E
authors.initials: E
authors.lastname: Zeldov
authors.forename: E
authors.initials: E
authors.lastname: Rumberger
authors.forename: D N
authors.initials: DN
authors.lastname: Hendrickson
authors.forename: G
authors.initials: G
authors.lastname: Christou