Microscopy and rock magnetism of fine grain-size titanomagnetite from the Jacupiranga Alkaline Complex, Brazil: unearthing Ti-magnesioferrite nanoparticles
| العنوان: | Microscopy and rock magnetism of fine grain-size titanomagnetite from the Jacupiranga Alkaline Complex, Brazil: unearthing Ti-magnesioferrite nanoparticles |
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| المؤلفون: | M.L. Rivas-Sánchez, Omar Ferreira Lopes, Avto Goguitchaishvili, Luis M. Alva-Valdivia, Jesús Arenas-Alatorre |
| المصدر: | Universidad Nacional Autónoma de México UNAM Redalyc-UNAM Geofísica Internacional (México) Num.2 Vol.52 |
| بيانات النشر: | Universidad Nacional Autónoma de México, 2013. |
| سنة النشر: | 2013 |
| مصطلحات موضوعية: | TMf nanoparticles, Materials science, Fine grain, Brasil, nanopartículas de titanomagnesio-ferrita, propiedades magnéticas, Analytical chemistry, Grain size effect, mineralogía, engineering.material, complejo alcalino Jacupiranga, Jacupiranga Alkaline Complex, Titanomagnetite, Magnesioferrite, General Energy, Geophysics, grain size effect, engineering, Ciencias de la Tierra, magnetic properties, mineralogy, efecto del tamaño de grano, Brazil |
| الوصف: | Very fine samples from the mineralized zones of the Jacupiranga complex at the Cajati mine were selected for crystallographic identification of Ti-magnesioferrite (TMf) nanostructures embedded in titanomagnetite (TM) using high-resolution transmission electron microscopy (TEM). A magnetic concentrate obtained of pyroxenite samples (sites 4 to 7) was reduced and divided into fractions of distinct range sizes: 26±2 μm, 19±1 μm, 13±1 μm, 9±1 μm, 6±1 μm and 6-0.1 μm. The mineralized samples of carbonatite and pyroxenite were characterized by X-ray diffraction, transmitted and reflected light microscope, and scanning electron microscope with multielemental analysis. The finest magnetic concentrate sample (MC6) was analyzed under high-resolution transmitted electron microscopy (TEM) and high angle annular dark field and Raman spectroscopy. Magnetic properties were measured for the distinct granulometric fractions, showing drastic changes when grain sizes go beyond the frontier from micro to nanometer sizes. Frequency-dependent magnetic susceptibility percentage (÷fd%) report higher values (10.2%) for the finer fractions (6±1 μm and 6-0.1 μm) attributed to dominant fractions of superparamagnetic particles. Nanometer and < 6 μm grain size TMf in TM particles require a magnetic field up to 249 mT to reach saturation during the isothermal remanent magnetization experiment. Coercivity and remanent magnetization of these samples increase when the particle size decreases, probably due to parallel coupling effects. Magnetic susceptibility versus temperature experiments were conducted two times on the same (< 35 nm) sample, showing that the repetition during the second heating is probably due to the formation of new TMf nanoparticles and growth of those already present during the first heating process. |
| وصف الملف: | application/pdf |
| اللغة: | English |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::8671ada32332946d66bb1111556b020c https://www.redalyc.org/articulo.oa?id=56826168001 |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi.dedup.....8671ada32332946d66bb1111556b020c |
| قاعدة البيانات: | OpenAIRE |
| الوصف غير متاح. |