title: Absence of orbital currents in superconducting YBa2Cu4O8 using a zeeman-perturbed nuclear-quadrupole-resonance technique.
abstract: Zeeman perturbed nuclear quadrupole resonance was applied to evaluate weak magnetic fields in the context of orbital currents in cuprate superconductors. The magnetic environment of the barium atom in c-axis oriented powder samples of YBa(2)Cu(4)O(8) was investigated in the pseudogap phase at 90 K. No evidence for orbital currents was found: any static and dynamic field must be less than 0.07 and 0.7 mT, respectively.
authors.affiliation: Physik-Institut, Universität Zürich, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Strässle
authors.forename: B
authors.initials: B
authors.lastname: Graneli
authors.forename: M
authors.initials: M
authors.lastname: Mali
authors.forename: J
authors.initials: J
authors.lastname: Roos
authors.forename: H
authors.initials: H
authors.lastname: Keller