Magnetostructural study of 2-(4-N-tert-butylaminoxylphenyl)benzimidazole.
The heat capacity of the title organic free radical, PhBABI, was measured over 0.3-300 K by adiabatic calorimetry and relaxation methods in the presence of external magnetic fields up to 9 T. A hump in the magnetic heat capacity was observed with a maximum at about 15 K in zero field, which did not shift at fields up to 9 T. The experimental magnetic entropy was in good agreement with the theoretical value of R ln 2 (= 5.76 J K(-1) mol(-1)) for S = 1/2 systems. The higher temperature, field-insensitive feature was fitted to several antiferromagnetic Heisenberg models. The best fits were obtained using spin ladder and coupled spin bilayer models.
Miyazaki
Yuji
Y
Research Center for Molecular Thermodynamics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan. miyazaki@chem.sci.osaka-u.ac.jp
Inaba
Akira
A
Sorai
Michio
M
Taylor
Patrick S
PS
Lahti
Paul M
PM