Publication: The effects of different barium doping concentration on the electrical and magnetotransport properties of magnetoresistive NBMO
Date
2025-03-13
Authors
Mohd Sofwan Mohd Safien
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Abstract
The effects of different Barium doping concentration on the electrical, structural, microstructural and magnetotransport properties in colossal magnetoresistive Nd1. Ba,MnO3 at x= 0.20, 0.25, 0.30 and 0.35 has been studied. All four samples were prepared through co-precipitation method at sintering temperature of 1200°C. Through X-ray diffraction measurement, all the samples are found to have an orthorhombic structure, single phase and can be indexed into Imma space group. The highest peak for every sample occurred in <200> direction. As the value of barium doping concentration increase, the insulator metal transition temperature, Tim is decreased except for sample with x=0.30. Magnetoresistance (MR) measurement was carried out in the presence of magnetic field ranging from 0.1 T to 1 T at room temperature. The highest value (~58%) of MR is obtained at sample with x=0.25 at 1 T. All the electrical resistivity data exceed 0.98 value in both equation of p(T) = Po + P2T2 and P(T) = Po + P2.5T2.5 at temperature lower than Tim, which indicates that the grain boundary effects, electron-electron scattering and electron magnon scattering process is highly responsible for the resistivity behavior. At paramagnetic insulating regions where T> Tim, variable range hopping (VRH) and small polaron hopping (SPH) model fit exceptionally well in the equations which signifies that the polaron hopping is responsible for the conductivity.
Description
TK 454.4 .M M63 2015