Propiedades estructuralesy magnéticas de aleaciones cristalinas desordenadas Fe50Mn25+xSn25-x con x: -1.25, 0.0, 2.5, 5.0, 7.5
| Autor: | Jorge Agüero, Wilber Pachín, Chachi Rojas, Justiniano Quispe, Carlos V. Landauro, Víctor A. Peña, Misael León, E. Baggio-Saitovitch, José J. Medina, Edson C. Passamani |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Magnetism Rietveld refinement Analytical chemistry Intermetallic General Physics and Astronomy Magnetic hysteresis Electronic Optical and Magnetic Materials Magnetization Geophysics History and Philosophy of Science Mössbauer spectroscopy Crystallite Physical and Theoretical Chemistry Solid solution |
| Zdroj: | MOMENTO. :43-62 |
| ISSN: | 2500-8013 0121-4470 |
| DOI: | 10.15446/mo.n62.87185 |
| Popis: | Disordered crystalline Fe50Mn25+xSn25-x alloys, with x = -1.25, 0.0, 2.5, 5.0, 7.5 (close to the full-Heusler alloys), were arc-melted in a high purity argon atmosphere and the molten pellets were individually sealed in quartz tubes also under argon atmosphere. Subsequently, they were annealed at 1173 K for 4 days, being finally quenched in a bath with cold water. Structural and magnetic properties have systematically been studied using X-ray diffraction, 57Fe, and 119Sn Mossbauer spectroscopies, and magnetization measurements recorded at room temperature. Rietveld refinement of the X-ray diffraction patterns of the annealed samples with x = -1.25 and 0 has revealed the presence of two hexagonal crystallographic phases: (i) a chemically disordered solid solution identified as e-(Fe/Mn)3Sn (majority fraction) and (ii) the e-Fe5Sn3 intermetallic compound (minority fraction). For samples with x = 2.5, 5.0, and 7.5, the Rietveld analysis has only indicated the presence of a chemically disordered solid solution identified as e-(Fe/Mn)3(Sn/Fe/Mn). Although compositions of the Fe50Mn25+xSn25-x alloys are close to that of full-Heusler alloys, none of them has the expected L21 structure. The average crystallite sizes, estimated from the Williamson-Hall method, are in the range of 256-62 nm. The average sizes has gradually decreased as the x-content is increased. Mossbauer results have shown localized-type magnetism from Fe non-equivalent sites, and itinerant-like magnetism on 119Sn-probes. Magnetic hysteresis loops, recorded at 300 K for a maximum field of 2200 Oe, have indicated that the remanent and coercive fields have systematically decreased as the x-parameter has increased. Coercive fields are in the range for soft magnets (1-20 Oe). |
| Databáze: | OpenAIRE |
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