Manjunatha, S. O. and Rao, Ashok and Awana, V. P. S. and Okram, G. S. (2015) Investigation on magnetic, electrical and thermoelectric power of Bi-substituted La0.8Ca0.2MnO3 manganites. Journal of Magnetism and Magnetic Materials, 394. pp. 130-137. ISSN 0304-8853

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In the present work, the structural, magnetic, magneto-transport and thermoelectric properties of polycrystalline compounds of La0.8-xBixCa0.2MnO3(0 <= x <= 0.1) compounds are reported. Structure refinement using Rietveld method confirms that the samples are single phased and crystallize in rhombohedral structure with R-3C space group. Magnetic studies reveal that the pristine sample exhibits T-C at 221 K and it shift towards lower temperature with Bi doping. Deviation of the temperature dependent of inverse susceptibility curves from the Curie-Weiss law confirms the existence of Griffiths-like phase. All the samples exhibit metal to insulator transition at temperature Tim which is found to decrease with increase in Bi doping which is consistent with the magnetic studies. Magneto-resistance MR% data shows that its peak value increases with Bi-doping. The analysis of electrical resistivity data in the metallic region (T < T-MI) suggests that the electron-electron scattering is predominant in this region whereas the insulating region (T > T-MI) is well described using Small polaron hopping (SPI1) and Motto variable range hopping (VRI-1) models. Analysis of thermoelectric power data in the high temperature region suggests that the SPH mechanism is operative in this regime, while the analysis of low temperature data reveals that the electron-magnon scattering is dominant in the region.

Item Type: Article
Uncontrolled Keywords: Griffiths phase Magneto-resistance Thermo-electric effect Variable rangehopping(VRH) Spin polarizedtunneling(SPT)
Subjects: Materials Science
Applied Physics/Condensed Matter
Depositing User: Dr. Rajpal Walke
Date Deposited: 28 Sep 2016 07:15
Last Modified: 28 Sep 2016 07:15

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