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Study of Structural and Electrical Transport Properties of Sn Doped La2Mn2O7

SHAHID HUSAIN1,* , M. WASI KHAN1

Affiliation

  1. Department of Physics, Aligarh Muslim University, Aligarh-202002, India

Abstract

The character of charge carriers in the manganites can be changed to n-type by replacing La3+ with tetravalent ions like Ce, Sn, Zr etc. A combination of n- and p-type oxides can form a p-n junction that can be used as a functional device for various applications. Therefore, the recently developed n-type La-Sn-Mn-O compound has attracted much research interest. We have synthesized the (La1-xSnx)2Mn2O7 (x = 0.1,0.2 and 0.3) in bulk form using solid state reaction route. These samples were characterized using x-ray diffraction and temperature dependence resistivity measurements. Rietveld analysis is performed using the FULLPROF code to ensure the single phase nature of the samples. PowderX technique is used for peak indexing and to determine the lattice parameters. The variation in lattice parameters has been observed and the unit cell volume increases with the increase in Sn concentration. The metal-insulator transition is observed for all the samples. We have fitted our resistivity data for the different temperature ranges, with the help of theoretical models. At low temperatures below transition temperature (Tc), the data fits well with the expression: ρ = ρ0 + ρ1T2.5. This suggests that electron-electron, electron-phonon, and electron-magnon interactions are responsible for variation in resistivity below Tc. The higher temperature data follows the relation: ρ(T) = ρ0T exp(Ea/kBT). This shows that the conductivity above the transition temperature is due to small polaron hopping..

Keywords

Manganites, Metal-insulator transition, Small polaron hopping.

Submitted at: April 1, 2008
Accepted at: July 1, 2008

Citation

SHAHID HUSAIN, M. WASI KHAN, Study of Structural and Electrical Transport Properties of Sn Doped La2Mn2O7, Journal of Optoelectronics and Advanced Materials Vol. 10, Iss. 7, pp. 1659-1662 (2008)