Publication Type
Journal
Journal Name
Physical Review Letters
Publication Date
Page Number
097201
Volume
108
Issue
9
Abstract
Using micromechanical force magnetometry, we have measured the magnetization of the strongleg
spin-1/2 ladder compound (C7H10N)2CuBr2 at temperatures down to 45 mK. Low-temperature
magnetic susceptibility as a function of field exhibits a maximum near the critical field Hc at which
the magnon gap vanishes, as expected for a gapped one-dimensional antiferromagnet. Above Hc 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 RW. The result supports the relation RW = 4K, where K is the Tomonaga-Luttinger-liquid
parameter.
