第40回 原研・兵県大合同コロキウム

日時: 平成20年3月19日(水) 14:00〜
Date and time: 19th March (Wed.) 14:00〜
場所: SPring-8, 萌光館
Place: SPring-8, "HOUKOUKAN" seminar room
Title: Ground state of one-dimensional conductor with local moments ; TPP[Fe(Pc)CN2]2
講演者: 花咲 徳亮 氏 (岡山大学理学部物理)
Speaker: Prof. Noriaki Hanasaki (Dept. of Physics, Okayama Univ.)
Abstract:

The molecular conductor TPP[Fe(Pc)CN2]2(∗) possesses the one-dimensional conduction electron system of the Pc π-electron interacted with the local moments of Fe 3d-electrons. The gigantic magnetoresistance is observed at the low temperatures, where the zero-field resistance is enhanced. The coincidence between the anisotropy of the magnetoresistance and that of the magnetic susceptibility indicates the correlation between the conduction and the local moments. In order to investigate the charge sector in the ground state, we measured the X-ray diffraction, and found the 4kF diffuse streak in Spring-8(BL02B1), suggesting the charge disproportionate state due to the nearest-neighbor Coulomb interaction. The correlation between this charge disproportionation in the π-band and the short-range antiferromagnetic state in the d-spin is of interest, which is an important factor for the gigantic response. We would like to discuss the ground state and the mechanism of the magnetoresistance.

(∗) Pc: phthalocyanine, TPP: tetraphenylphosphonium