Metal-insulator transitions in pressed pellets of BF4 - doped poly(3-methylthiophene)
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Data
1997-12-01
Autores
Pawlicka, A.
Pereira, E. C.
Nascimento, O. R.
Bulhões, L. O. S.
Walmsley, L. [UNESP]
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Resumo
From Electron Spin Resonance (ESR) data in pressed pellets of BF4 - doped Poly(3-methylthiophene) (P3MT) we obtained simultaneously the paramagnetic susceptibility and. the microwave conductivity. We observed a transition from a high-temperature insulator state to a room-temperature metallic state. Around 240K. evidence of a Peierls transition is observed, but if the sample is slowly cooled, this transition is partially suppressed. DC conductivity data taken with the sample quenched to 79 K show a non-linear I-V response for very small electric fields, suggesting depinning of Charge-Density Wave (CDW). The data for heating and cooling the system above room temperature, indicate the formation of bipolarons.
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Charge-density waves, Conducting polymers, Electron spin resonance, Metal-insulator transitions, Aromatic compounds, Boron compounds, Conductive plastics, Electric conductivity of solids, Electron spin resonance spectroscopy, Microwave conductivity, Paramagnetic susceptibility, Peierls transition, Phase transitions
Como citar
Phase Transitions, v. 62, n. 3 SEC. A, p. 157-165, 1997.