Zn-doping effect on the energy barrier to magnetization reversal in superparamagnetic nickel ferrite nanoparticles
Measurements of ac-susceptibility and dc-magnetization were carried out on samples of Ni1−xZnxFe2O4 nanoparticles (x = 0, 0.25, 0.5, 0.75) with average diameters D ≈ 7 nm. Values of the superparamagnetic blocking temperature TB were obtained from the characteristic temperature behavior of the imagin...
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| Tipo de recurso: | artículo |
| Estado: | Versión enviada para evaluación y publicación |
| Fecha de publicación: | 2007 |
| País: | México |
| Institución: | Centro de Investigación en Materiales Avanzados |
| Repositorio: | Fuente de Objetos Científicos Open Access del CIMAV |
| Idioma: | inglés |
| OAI Identifier: | oai:cimav.repositorioinstitucional.mx:1004/1004 |
| Acceso en línea: | http://cimav.repositorioinstitucional.mx/jspui/handle/1004/1004 |
| Access Level: | acceso abierto |
| Palabra clave: | info:eu-repo/classification/Zn-doping/Nickel info:eu-repo/classification/cti/1 info:eu-repo/classification/cti/22 info:eu-repo/classification/cti/2299 info:eu-repo/classification/cti/229999 |
| Sumario: | Measurements of ac-susceptibility and dc-magnetization were carried out on samples of Ni1−xZnxFe2O4 nanoparticles (x = 0, 0.25, 0.5, 0.75) with average diameters D ≈ 7 nm. Values of the superparamagnetic blocking temperature TB were obtained from the characteristic temperature behavior of the imaginary susceptibility χimag. An Arrhenius-type law, which accurately describes the relationship between the observation time τobs and the blocking temperature, was used to determine the effective energy barrier to magnetization reversal Ueff. A Zn-content dependence of the energy barrier is observed, where Ueff changes little for 0 ≤ x ≤ 0.25, it peaks at x = 0.5, and decreases back upon further Zn-doping. The large increase of Ueff at x = 0.5 is attributed to an enhanced magnetic anisotropy induced by the crossover between two spatial arrangements of spins in the A and B sub-lattices of the ferrimagnetic inverse spinel. |
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