LOW-TEMPERATURE HEAT-CAPACITY AND MAGNETIC-SUSCEPTIBILITY OF DPPH-BENZENE COMPLEX

An experimental study of the heat capacity in fields of 0 and 50 kOe from 0.55 to 20 K and the powder magnetic susceptibility from 0.4 K to room temperature of the DPPH-benzene complex is reported. Magnetic and lattice contributions to the heat capacity are well resolved. The susceptibility and magnetic heat capacity are compared with pair, chain, and quadratic net Heisenberg model predictions, none of which give satisfactory agreement with experiment. Calculations based on McConnell's spin density Hamiltonian indicate the likelihood that dominant intermolecular exchange coupling is of comparable magnitude to six near neighbors, in layers separated from adjacent layers by benzene solvent molecules. © 1978 American Institute of Physics.