Abstract： The electrical transport and magnetic properties of colossal
magnetoresistance material FeCr2S4 are studied. The temperature dependence of resistivity ρ and thermoelectric power S are investigated from 5 to 300 K and from 77 to 300 K, respectively. The activation energy Eρ obtained from ρ-T is larger than the activation energy ES, obtained from S-T. This indicates that magnetic polarons dominate the conduction behaviour at temperatures above Tc. The M-T curve and electron spin resonance spectra show that the paramagnetic-ferromagnetic transition is incomplete, and that a paramagnetic phase coexists with a ferromagnetic phase in a certain temperature range below Tc. It is proposed that the insulator-metal transition near Tc could be attributed to the gradual delocalizing effect from magnetic polarons to naked carriers. The resistivity in the presented temperature range can be described by considering the coexistence of magnetic polarons and naked carriers.
(Conductivity phenomena in semiconductors and insulators)
引用本文:
YANG Zhao-Rong;TAN Shun;CHEN Zhi-Wen;ZHANG Yu-Heng. Delocalizing Effect of Polarons in Colossal Magnetoresistance
Material FeCr2S4[J]. 中国物理快报, 2001, 18(4): 604-607.
YANG Zhao-Rong, TAN Shun, CHEN Zhi-Wen, ZHANG Yu-Heng. Delocalizing Effect of Polarons in Colossal Magnetoresistance
Material FeCr2S4. Chin. Phys. Lett., 2001, 18(4): 604-607.
2001, Vol. 18 
