Magnetotransport, thermoelectric power, thermal conductivity and specific heat of Pr(2/3)Sr(1/3)MnO(3) manganite

作者：Panwar Neeraj; Rao Ashok; Singh R S; Syu W K; Kaurav N; Kuo Y K^*; Agarwal S K

来源：Journal of Applied Physics, 2008, 104(8): 083906.

DOI：10.1063/1.2992521

Magnetotransport and thermal studies of Pr(2/3)Sr(1/3)MnO(3) polycrystalline sintered bulk sample are reported here. The resistivity rho(T) and thermoelectric power S(T) data show an insulator to metal (I-M) phase transition at T(P) approximate to 294 K and T(S) approximate to 290 K, respectively. Magnetization measurement confirms that the sample undergoes a transition from paramagnetic to ferromagnetic phase at a defined Curie temperature T(C) = 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 T(P), 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 similar to 100 K (signifying a crossover from Umklapp to defect-limited scattering) have also been noticed. Specific

• 出版日期2008-10-15
• 单位东华大学