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Tunneling charge transfer in manganise oxides.

Victoria N. Leonova 1Vladimir M. Svistunov 1Mikhail A. Belogolovskii 2Henryk Szymczak 3

1. National Technical University"Kharkov Polytechnical Institute", 21 Frunze str., Kharkov 61002, Ukraine
2. National Academy of Sciences of Ukraine, A.Galkin Donetsk Institute for Physics & Technology (DonPTI NASU), Roza Luxemburg 72, Donetsk 83114, Ukraine
3. Polish Academy of Sciences, Institute of Physics, al. Lotników 32/46, Warszawa 02-668, Poland

Abstract

Tunneling measurements of manganite ceramic samples exhibiting a CMR effect in a wide range of voltages are performed. The analysis of the background conductance spectra was carried out and an assertion in support of the presence of nanoscale metallic regions embedded into the insulating matrix was presented. We argue that this phenomena can be caused by the phase separation in the near-barrier region. The data obtained are discussed in terms of the Glasman-Matveev model for localized states in the barrier and these localizons can stimulate the resonance mechanism for tunneling transfer of charge in systems. Effective spectral functions of the electron-boson interaction have been extracted from a fine structure in the conductance curves. It is supposed that structure between 100 and 200 meV may be attributed to the orbital ordering in manganite. Experiments with high-voltage treatments exhibit a tendency of the suppression of the electron-phonon interaction with increasing disorder at the manganite surfaces, as it follows from the theory of weak localization effects.

 

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Related papers

Presentation: Poster at E-MRS Fall Meeting 2007, Symposium J, by Victoria N. Leonova
See On-line Journal of E-MRS Fall Meeting 2007

Submitted: 2007-05-14 00:36
Revised:   2009-06-07 00:44