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Voltage and temperature dependence of the grain boundary tunneling magnetoresistance in manganites

C. Hoefener·J. B. Philipp·J. Klein·L. Alff·A. Marx·B. Buechner·R. Gross
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Abstract

We have performed a systematic analysis of the voltage and temperature dependence of the tunneling magnetoresistance (TMR) of grain boundaries (GB) in the manganites. We find a strong decrease of the TMR with increasing voltage and temperature. The decrease of the TMR with increasing voltage scales with an increase of the inelastic tunneling current due to multi-step inelastic tunneling via localized defect states in the tunneling barrier. This behavior can be described within a three-current model for magnetic tunnel junctions that extends the two-current Julliere model by adding an inelastic, spin-independent tunneling contribution. Our analysis gives strong evidence that the observed drastic decrease of the GB-TMR in manganites is caused by an imperfect tunneling barrier.

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C. Hoefener, J. B. Philipp, J. Klein, L. Alff, A. Marx, B. Buechner, R. Gross. 2000-05-09. Voltage and temperature dependence of the grain boundary tunneling magnetoresistance in manganites. https://doi.org/10.1209/epl%2Fi2000-00324-1

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