Ferromagnetic anomaly associated with the antiferromagnetic transitions in (donor)[Ni(mnt)2]-type charge-transfer salts.
Three newly prepared [Ni(mnt)2] complexes, (HMTTF)[Ni(mnt)2], (ChSTF)[Ni(mnt)2], and (DBTTF)2[Ni(mnt)2], are reported (DBTTF = dibenzotetrathiafulvalene, ChSTF = 2,3-cyclohexylenedithio-1,4-dithia-5,8-diselanafulvalene, HMTTF = bis(trimethylene)-tetrathiafulvalene, and mnt = maleonitrile dithiolate). The former two compounds have usual DA-type (D = donor, A = acceptor) mixed stacks, whereas the DBTTF complex has DDDDAA-type 6-fold columns. These compounds are electrical insulators, but the HMTTF and ChSTF complexes exhibit chiT minima at 16 and 55 K, respectively, followed by chiT peaks at 8 and 16 K. Below these temperatures the ESR signal disappears, indicating antiferromagnetic transitions. The origin of the ferromagnetic interaction is explained either from the difference of the g values between the donor and the anion or from the intrinsic ferromagnetic interaction of the [Ni(mnt)2] anions.
Nakajima
Hideyasu
H
Department of Organic and Polymeric Materials, Graduate School of Science and Engineering, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan.
Katsuhara
Mao
M
Ashizawa
Minoru
M
Kawamoto
Tadashi
T
Mori
Takehiko
T