title: 77Se NMR probe of magnetic excitations of the magic angle effect in (TMTSF)2PF6.
abstract: We report 77Se spin-lattice relaxation rates for (TMTSF)2PF6, carried out in the regime where a set of spectacular transport anomalies known as the "magic angle effects" are observed. In situ resistance measurements (R(zz)) were used to verify the experimental conditions and give precise sample alignment information. We found that the 77Se T-11 exhibits no significant changes as the magnetic-field orientation is rotated through the magic angles, and conclude that there is no evidence for either a single-particle gap or a spin gap. The clearly observed field-induced spin-density wave transition temperature is also, unexpectedly, not enhanced at the magic angles.
authors.affiliation: Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Weida
authors.initials: W
authors.lastname: Wu
authors.forename: P M
authors.initials: PM
authors.lastname: Chaikin
authors.forename: W
authors.initials: W
authors.lastname: Kang
authors.forename: J
authors.initials: J
authors.lastname: Shinagawa
authors.forename: W
authors.initials: W
authors.lastname: Yu
authors.forename: S E
authors.initials: SE
authors.lastname: Brown