Magnetic specific heat studies of two Ising spin 1/2 chain systems M(N_3)_2(bpy)

摘要

M(N_3)_2(bpy) [where M = Cu(II), Co(II), N_3 = azide, and bpy = 4,4'-bipyridine] are two newly synthesized metal-organic framework (MOF) systems, in which the divalent M ions are connected though the azide ligands forming almost ideal magnetic 1 D chains. Specific heat measurements were performed on these compounds and the magnetic specific heats were deduced using appropriate methods for estimating the lattice specific heat. The magnetic specific heat data were analyzed and fit to the Ising model. The exchange interaction J/k_B values of 13.1 K for Cu(N_3)_2(bpy) and 8.2 K for Co(N_3)_2(bpy) were obtained and compared to the J values from fitting the measured magnetic susceptibility data.