Nath, Rajib and Raychaudhuri, A K and Mukovskii, Ya M and Mondal, Parthasarathi and Bhattacharya, Dipten and Mandal, P (2013) Electric field driven destabilization of the insulating state in nominally pure LaMnO3. Journal of Physics-Condensed Matter, 25 (15). Article No. ISSN 0953-8984

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We report an electric field driven destabilization of the insulating state in nominally pure LaMnO3 single crystal with a moderate field which leads to a resistive state transition below 300 K. The transition is between the insulating state in LaMnO3 and a high resistance bad metallic state that has a temperature independent resistivity. The transition occurs at a threshold field (E-th) that shows a steep enhancement on cooling. While at lower temperatures the transition is sharp and involves a large change in resistance, it softens on heating and is eventually absent above 280 K. When the Mn4+ content is increased by Sr substitution up to x = 0.1, the observed transition, although observable in a certain temperature range, softens considerably. This observation has been explained as a bias driven percolation type transition between two co-existing phases, where the majority phase is a charge and orbitally ordered polaronic insulating phase and the minority phase is a bad metallic phase. The mobile fraction f of the bad metallic phase deduced from the experimental data follows an activated kinetics as f = f(o) (E) exp(-Delta/k(B)T) with the activation energy Delta approximate to 200 meV, and the pre-factor f(o) (E) is a strong function of the field that leads to a rapid enhancement of f on application of field, leading to the resistive state transition. We suggest likely scenarios for such co-existing phases in nominally pure LaMnO3 that can lead to the bias driven percolation type transition.

Item Type: Article
Subjects: Electronics
Divisions: Nano-Structured Materials
Depositing User: Bidhan Chaudhuri
Date Deposited: 13 Sep 2013 09:23
Last Modified: 12 Mar 2016 18:30

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