| Revista: | Materials research |
| Base de datos: | PERIÓDICA |
| Número de sistema: | 000312401 |
| ISSN: | 1516-1439 |
| Autores: | Albuquerque, Adriana Silva de1 Ardisson, Jose Domingos Bittencourt, Edison Macedo, Waldemar Augusto de Almeida |
| Instituciones: | 1Universidade Estadual de Campinas, Campinas, Sao Paulo. Brasil |
| Año: | 1999 |
| Periodo: | Jul |
| Volumen: | 2 |
| Número: | 3 |
| Paginación: | 235-238 |
| País: | Brasil |
| Idioma: | Inglés |
| Tipo de documento: | Artículo |
| Enfoque: | Experimental |
| Resumen en inglés | Granular systems composed by nanostructured magnetic materials embedded in a non-magnetic matrix present unique physical properties that depend crucially on their nanostructure. In this work, we have studied the structural and magnetic properties of NiZn-ferrite nanoparticles embedded in SiO2, a granular system synthesized by sol-gel processing. Samples with ferrite volumetric fraction x ranging from 6% to 78% were prepared, and characterized by X-ray diffraction, Mössbauer spectroscopy and vibrating sample magnetometry. Our results show the formation of pure stoichiometric NiZn-ferrite in the SiO2 matrix for x < 34%. Above these fraction, our samples presented also small amounts of Fe2O3. Mössbauer spectroscopy revealed the superparamagnetic behaviour of the ferrimagnetic NiZn-ferrite nanoparticles. The combination of different ferrite concentration and heat treatments allowed the obtaintion of samples with saturation magnetization between 1.3 and 68 emu/g and coercivity ranging from 0 to 123 Oe, value which is two orders of magnitude higher than the coercivity of bulk NiZn-ferrite |
| Disciplinas: | Ingeniería |
| Palabras clave: | Ingeniería de control, Ingeniería química, Materiales granulares, Magnetización, Nanoestructuras, Ferritas |
| Keyword: | Engineering, Chemical engineering, Control engineering, Granular materials, Magnetization, Nanostructures, Ferrites |
| Texto completo: | Texto completo (Ver HTML) |
