title: Wilson ratio of a Tomonaga-Luttinger liquid in a spin-1/2 Heisenberg ladder.
abstract: Using micromechanical force magnetometry, we have measured the magnetization of the strong-leg spin-1/2 ladder compound (C(7)H(10)N)(2)CuBr(2) at temperatures down to 45 mK. Low-temperature magnetic susceptibility as a function of field exhibits a maximum near the critical field H(c) at which the magnon gap vanishes, as expected for a gapped one-dimensional antiferromagnet. Above H(c) a clear minimum appears in the magnetization as a function of temperature, as predicted by theory. In this field region, the susceptibility in conjunction with our specific-heat data yields the Wilson ratio R(W). The result supports the relation R(W)=4K, where K is the Tomonaga-Luttinger-liquid parameter.
authors.affiliation: Department of Physics, University of Florida, Gainesville, Florida 32611, USA.
authors.forename: K
authors.initials: K
authors.lastname: Ninios
authors.forename: Tao
authors.initials: T
authors.lastname: Hong
authors.forename: T
authors.initials: T
authors.lastname: Manabe
authors.forename: C
authors.initials: C
authors.lastname: Hotta
authors.forename: S N
authors.initials: SN
authors.lastname: Herringer
authors.forename: M M
authors.initials: MM
authors.lastname: Turnbull
authors.forename: C P
authors.initials: CP
authors.lastname: Landee
authors.forename: Y
authors.initials: Y
authors.lastname: Takano
authors.forename: H B
authors.initials: HB
authors.lastname: Chan