Magnetic properties of a molecular-based spin-ladder system:(5IAP)2CuBr4⋅2H2O

Abstract

We have synthesized and characterized a spin-1/2 Heisenberg antiferromagnetic ladder: bis 5-iodo-2-aminopyridinium tetrabromocuprate (II) dihydrate. X-ray diffraction studies show the structure of the compound to consist of well isolated stacked ladders and the interaction between the ${\mathrm{Cu}}^{2+}$ atoms to be due to direct $\mathrm{Br}\ensuremath{\cdot}\ensuremath{\cdot}\ensuremath{\cdot}\mathrm{Br}$ contacts. Magnetic susceptibility and magnetization studies show the compound to be in the strong-coupling limit, with the interaction along the rungs ${(J}^{\ensuremath{'}}\ensuremath{\approx}13\mathrm{K})$ much greater than the interaction along the rails $(J\ensuremath{\approx}1\mathrm{K}).$ Magnetic critical fields are observed near 8.3 and 10.4 T, respectively, establishing the existence of the energy gap.