Impact of silver substitution on the magnetotransport and thermal behavior of polycrystalline Sm0.55Sr0.45−xAgxMnO3 (x = 0 & 0.15) manganites
| Autor: | Anchit Modi, Shovit Bhattacharya, Masroor Ahmad Bhat, Tarachand, G. S. Okram, N. K. Gaur |
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| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Materials science Condensed matter physics Rietveld refinement Mechanical Engineering Transition temperature Metals and Alloys 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Variable-range hopping Magnetization Mechanics of Materials Seebeck coefficient 0103 physical sciences Thermoelectric effect Materials Chemistry Curie temperature 0210 nano-technology Temperature coefficient |
| Zdroj: | Journal of Alloys and Compounds. 691:230-238 |
| ISSN: | 0925-8388 |
| DOI: | 10.1016/j.jallcom.2016.08.222 |
| Popis: | We have synthesized a series of Sm 0.55 Sr 0.45−x Ag x MnO 3 (x = 0 & 0.15) by conventional solid state reaction method to scrutinize the effect of monovalent Ag + as a replacement of Sr 2+ ion on structural, electrical, magnetotransport and thermoelectric properties. The structural parameters obtained using Rietveld refinement of X-ray diffraction data which showed perovskite structure having orthorhombic ( Pnma ) symmetry without any detectable impurity phase. It is observed that M ZFC and M FC curves become more manifested as Ag + content is increased which indicates an increase in magnetic frustration arising due to bending of Mn-O-Mn bond. The M-H plots show the narrow hysteresis loops which indicate the soft ferromagnetic nature. Magnetic studies also show that the Curie temperature T C is found to decrease with Ag + content. The metal–insulator transition temperature (T MI ) is observed which decreases with the increase of Ag + content when magnetic field is applied. The resistivity data in high temperature region are explained within the framework of variable range hopping (VRH) and small polaron hopping (SPH) models. The thermoelectric power (S) of the reported samples exhibits a crossover from positive to negative value and value of S increases in doped samples. The analysis of thermoelectric power data confirms that the small polaron hopping model in high temperature region and at low temperature electron–magnon scattering is the dominating in the FM region. With increasing the Ag + content the samples showed very high magneto-resistance (MR%) and temperature coefficient of resistance (TCR%) which make the compound more promising for scientific and technological applications. |
| Databáze: | OpenAIRE |
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