Evidence of weak ferromagnetism in doped plasticized polyaniline (PANI-DDoESSA)0.5 from electron spin resonance measurements

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2013-03-20

Autores

Santana, V. T. [UNESP]
Nascimento, O. R.
Djurado, D.
Travers, J. P.
Pron, A.
Walmsley, L. [UNESP]

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Resumo

X-band electron spin resonance (ESR) measurements have been performed on a conducting free-standing film of polyaniline plasticized and protonated with di-n-dodecyl ester of sulfosuccinic acid (DDoESSA). The magnetic field was applied parallel and perpendicular to the plane of the film. At around 75 K a transition is observed from Pauli susceptibility to a localized state in which the spin 1/2 polarons behave as spin 1/2 dimers. A rough estimation of the intradimer and interdimer exchange constants is obtained. Below 5 K, ESR data reveal a weak ferromagnetism with the Dzyaloshinskii-Moriya vector mainly oriented in the plane of the film. The existence of a relatively well-defined n-fold axis along the chain direction in the crystalline regions confers a symmetry compatible with such analysis. © 2013 IOP Publishing Ltd.

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A transitions, Chain direction, Crystalline regions, Dzyaloshinskii-moriya, Electron spin resonance measurements, Exchange constants, Freestanding films, Localized state, Protonated, Rough estimation, Spin 1/2, Weak ferromagnetism, X-band electron spin resonances, Polyaniline, Ferromagnetism

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Journal of Physics Condensed Matter, v. 25, n. 11, 2013.