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Annealing effect on transport properties of $Nd_{0.67}Sr_{0.33}MnO_{3}$ thin films

Pattabiraman, M and Murugaraj, P and Rangarajan, G and Prasad, V and Subramanyam, SV and Sastry, VS and Koo, Sang-Mo and Rao, KV (2000) Annealing effect on transport properties of $Nd_{0.67}Sr_{0.33}MnO_{3}$ thin films. In: Pramana Journal Of Physics, 55 (3). pp. 455-469.


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Annealing dependence of the lattice parameter, resistivity, magnetoresistance and thermopower have been studied on $Nd_{0.67}Sr_{0.33}MnO_{3}$ thin films deposited on $LaAlO_{3}$ and alumina substrates by pulsed laser ablation. Upon annealing at 800 degree C and 1000 degree C the lattice constant of the LaAlO3 film tends toward that of the bulk target due to reduction in oxygen vacancies. This results in a metal-insulator transition at temperatures which increase with progressive annealing along with a decrease in the observed low temperature MR. Using a magnon scattering model we estimate the eg bandwidth of the film annealed at 1000 degree C and show that the magnon contribution to the resistivity is suppressed in a highly oxygen deficient film and gains prominence only upon subsequent annealing.We also show that upon annealing, the polaron concentration and the spin cluster size increases in the paramagnetic phase, using an adiabatic polaron hopping model which takes into account an exchange dependent activation energy above the resistivity peak.

Item Type: Journal Article
Publication: Pramana Journal Of Physics
Publisher: Indian Academy of Sciences
Additional Information: Copyright for this article belongs to Indian Academy of Sciences
Keywords: Colossal magnetoresistance;polaron;metal-insulator transition;thermopower;oxygen deficiency;manganite
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 13 Dec 2005
Last Modified: 19 Sep 2010 04:15
URI: http://eprints.iisc.ac.in/id/eprint/1764

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