Magnetotransport, thermoelectric power, thermal conductivity and specific heat of Pr2/3Sr1/3MnO3 manganite

Panwar, Neeraj and Rao, Ashok and Singh, R S and Syu, W K and Kaurav, N and Kuo, Y K and Agarwal, S K (2008) Magnetotransport, thermoelectric power, thermal conductivity and specific heat of Pr2/3Sr1/3MnO3 manganite. Journal of Applied Physics, 104.

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Abstract

Magnetotransport and thermal studies of Pr2/3Sr1/3MnO3 polycrystalline sintered bulk sample are reported here. The resistivity ��T� and thermoelectric power S�T� data show an insulator to metal I-M� phase transition at TP�294 K and TS�290 K, respectively. Magnetization measurement confirms that the sample undergoes a transition from paramagnetic to ferromagnetic phase at a defined Curie temperature TC=280 K. A substantial increase in magnetoresistance from 2.5% at 280 K to 5% at 77 K has been noticed in a low magnetic field 0.15 T. Small polaron hopping model is found to be operative above the transition temperature TP, whereas electron-electron and electron-magnon scattering processes govern the low temperature metallic behavior. A detailed analysis of thermoelectric power in the ferromagnetic regime suggests that the complicated temperature dependence of S may be understood on the basis of electron-magnon scattering. A transition from decreasing high temperature thermal conductivity �due to local anharmonic distortions associated with small polarons�, to an increasing thermal conductivity �due to decreasing of phonon-phonon scattering� and thereafter a peak at �100 K �signifying a crossover from Umklapp to defect-limited scattering� have also been noticed. Specific heat measurements depict a pronounced anomaly near the TC, indicating the magnetic ordering and magnetic inhomogeneity in the sample.

Item Type: Article
Subjects: Engineering > MIT Manipal > Physics
Depositing User: MIT Library
Date Deposited: 11 Mar 2014 11:35
Last Modified: 11 Mar 2014 11:35
URI: http://eprints.manipal.edu/id/eprint/139070

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