Magnetization of staggered S = 1/2 antiferromagnetic Heisenberg chain systems

Cu Pyrimidine Cu(C4N2H4)(NO3)2(H2O)2 and Cu Benzoate Cu(C6H5COO)2·3H2O are molecule-based S = 1/2 antiferromagnetic Heisenberg chain systems. Because of a staggering of the g tensor and the Dzyaloshinskii-Moriya interaction, the magnetic prinicpal axis system a''bc'' is distinct from the crystallographic unit cell. Along a'' a behavior corresponding to the uniform S = 1/2 antiferromagnetic Heisenberg chain occurs, while along c'' the effect of staggering of the g tensor and Dzyaloshinskii-Moriya interaction are most prominent. Here, we discuss the field and temperature dependent magnetization along a'' and c'' of these systems, in particular with respect to the relevance of the inhomogeneity parameter k controlling the ratio between longitudinal and transverse magnetization components