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.
Research Center for Molecular Thermodynamics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan. miyazaki@chem.sci.osaka-u.ac.jp
Yuji
Y
Miyazaki
Akira
A
Inaba
Michio
M
Sorai
Patrick S
PS
Taylor
Paul M
PM
Lahti