Particle size and magnetic field dependent resistivity and thermoelectric power of La0.5Pb0.5MnO3 above and below metal–insulator transition

2002 ◽  
Vol 91 (8) ◽  
pp. 5125-5134 ◽  
Author(s):  
Aritra Banerjee ◽  
Sudipta Pal ◽  
S. Bhattacharya ◽  
B. K. Chaudhuri ◽  
H. D. Yang
Keyword(s):  
Magnetic Field ◽  
Particle Size ◽  
Thermoelectric Power ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Field Dependent

Particle Size Dependent Magnetoresistance And Magnetothermoelectric Power Of La0.5Pb0.5MnO3 Showing Metal-Insulator Transition

2002 ◽  
Vol 718 ◽  
Author(s):  
Aritra Banerjee ◽  
S Pal ◽  
B K Chaudhuri
Keyword(s):  
Magnetic Field ◽  
Particle Size ◽  
Low Temperature ◽  
Nearest Neighbor ◽  
Small Polaron ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Polaron Hopping ◽  
Size Dependent

AbstractParticle size dependent transport properties (resistivity and thermopower) of La0.5Pb0.5MnO3 has been investigated both in presence and in absence of magnetic field B=0.0-1.5T (maximum). All the samples show metal-insulator transition (MIT) with a peak at the MIT temperature (Tp). Magnetic field decreases the resistivity with an increase in the peak temperature Tp. Particle size, conductivity and Tp of the sample increase with increasing annealing time. High temperature semiconducting (insulating) part of the resistivity curve is divided into two distinct regimes. Resistivity data for T>qθ/2, can be well fitted with the nearest neighbor small polaron hopping (SPH) model. Polaron hopping energy (WH) decreases with increase of particle size. The lower temperature part (Tp>T>qθ/2) of the semiconducting (insulating) regime is found to follow variable range hopping (VRH) model. With the increase of particle size, the temperature range of validity of the VRH mechanism decreases. The low temperature metallic regime (for T<Tp) of the resistivity (both in absence and in presence of field) data fit well with ρ = ρ0 +ρ2.5 T2.5 and transport mechanism in this region is mainly dominated by magnon-carrier scattering (∼T2.5). Particle size has, however, comparatively little effect on Seebeck coefficient (S). In all the samples with different particle sizes, S changes sign below Tp. In contrast to magnetoresistance, application of magnetic field increases S at low temperature (T<Tp) for these samples. Similar to the resistivity results, thermopower data in the metallic phase (both for B=0.0 and 1.5T) can also be analyzed by considering magnon-scattering term along with an additional spin-wave fluctuation term (∼T4).

scholarly journals Electronic thermoelectric power factor and metal-insulator transition in FeSb2

2012 ◽  
Vol 86 (11) ◽  
Author(s):  
Qing Jie ◽  
Rongwei Hu ◽  
Emil Bozin ◽  
A. Llobet ◽  
I. Zaliznyak ◽  
...  
Keyword(s):  
Thermoelectric Power ◽  
Power Factor ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Thermoelectric Power Factor ◽  
Metal Insulator
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