Static properties of a ferromagnetic S=1/2 chain system with orthorhombic exchange anisotropy: Comparison of numerical results and experimental data on [C6H11NH3]CuCl3

Results of the numerical quantum-transfer-matrix method (QTM) are compared with experimental data on [C6H11NH3]CuCl3, a quasi-one-dimensional ferromagnetic S=1/2 system with orthorhombic exchange anisotropy. The experimentally observed static properties of this system, such as magnetization, susceptibility, and heat capacity, generally can be described with an accuracy comparable to the experimental error. At temperatures extending up to a few kelvin above the three-dimensional-ordering temperature systematic deviations between theory and the data are found; they are attributed to the (very small) coupling between the chains in this compound.