Magnetic anisotropy and weak ferromagnetism of single crystal 1,3,5-triphenyl-6 oxoverdazyl organic free radical

摘要

The anisotropic spontaneous magnetization M_0(T) and antiferromagnetic suseeptibility x(T) of 1,3,5,-triphenyl-6-oxoverdazyl (TOV) radical in single crystal form are reported as a function of applied magnetic field (H), with H parallel to three crystal axes. The temperature dependence of the weak ferromagnetic (WFM) spontaneous magnetization was derived from extrapolation of the magnetization data between 0.1 T and 0.3T to 0.0 T, in the temperature region from 2.0 up to 10.0 K. Besides, the anisotropic antiferromagnetic susceptibility was derived from more higher fields magnetization data, which the range of applied field was up to 2.0 T. WFM behavior, due to spin canting, is found for T<=T_N(=5.5 +-0.2K) along the a,b and c axes of the TOV single crystal, where the value of M_0=14+-2, 30+-2 and 44+-2 emu/mol at 2.0 K, respectively. The possible irreducible correpresentations for the weak ferromagnetism of the TOV single crystal have been discussed, and the magnetic spin structure in the unit cell was also clearly determined without neutron diffraction data.