Metallic Transport and Ferrimagnetic Interaction Achieved by Band Filling Control in Organic Conductors; β '-ET3(MCl42-)2-x(M'Cl41-)x [M = Co, Zn, M' = Ga, Fe]
Abstract
The systematic band-filling control has been performed in β'-ET3(MCl42-)2-x(M'Cl41-)x (ET = bis(ethylenedithio)tetrathiafulvalene, M = Co, Zn, M' = Ga, Fe, x = 0--1.24). By means of band-filling control to the parent narrow-gap semiconductor, β'-ET3(ZnCl42-)2, the conductivity at room temperature (rt) is increased from 0.2 S cm-1 to 50 S cm-1 (M' = Ga, x = 0.44) and the metallic behavior is observed down to 90 K. The increase of resistivity below 90 K caused by the randomness of the anion potential is suppressed by the external pressure and the metallic behavior is maintained down to 3 K. The thermoelectric power measurements and their fitting based upon the band calculation demonstrate that the doping occurs at the two-dimensional donor layer and the one-dimensional array for β'-ET3(CoCl42-)0.76(FeCl41-)1.24. Moreover, the introduction of the magnetic anions for β'-ET3(CoCl42-)1.20(FeCl41-)0.80 affords the ferrimagnetic interaction between Co2+ (S = 3/2) and Fe3+ (S=5/2) through the doped carriers.
- Publication:
-
Journal of the Physical Society of Japan
- Pub Date:
- July 2005
- DOI:
- 10.1143/JPSJ.74.2061
- Bibcode:
- 2005JPSJ...74.2061S