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AC-Susceptibility Measurements of the Superparamagnetic Relaxation in Systems of Ni1−xZnxFe2O4 Nanoparticles

Published online by Cambridge University Press:  01 February 2011

Antony Adair
Affiliation:
[email protected], University of Texas at El Paso, Physics, Physics Department, 500 West University, El Paso, TX, 79968, United States
Jose T. Elizalde Galindo
Affiliation:
[email protected], University of Texas at El Paso, Physics, El Paso, TX, 79968, United States
Cristian Botez
Affiliation:
[email protected], University of Texas at El Paso, Physics, El Paso, TX, 79968, United States
Verónica Corral Flores
Affiliation:
[email protected], Centro de Investigación en Materials Avanzados, Chihuahua, N/A, Mexico
Dario Bueno Baques
Affiliation:
[email protected], Centro de Investigación en Materials Avanzados, Chihuahua, N/A, Mexico
Luis Fuentes Cobas
Affiliation:
[email protected], Centro de Investigación en Materials Avanzados, Chihuahua, N/A, Mexico
José A. Matutes-Aquino
Affiliation:
[email protected], Centro de Investigación en Materials Avanzados, Chihuahua, N/A, Mexico
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Abstract

We have investigated the effect of Zn-doping on the superparamagnetic relaxation of nanosized nickel ferrite particles. Our temperature-resolved AC-susceptibility data demonstrate that the relaxation of these systems is well described by an Arrhenius-type law, behavior which allows a precise determination of the effective energy barrier to magnetization reversal, Ueff. We observe that the Zn-content dependence of Ueff exhibits a pronounced maximum when half on the magnetic Ni2+ ions are replaced by nonmagnetic Zn2+. The average blocking temperature (measured at a given frequency) shows a similar behavior. The observed increase of Ueff is attributed to an enhanced magnetic anisotropy induced by the crossover between two magnetocrystalline regimes. Our findings demonstrate the ability to control the superparamagnetic relaxation of ferrimagnetic spinel nanoparticles through chemical manipulations.

Keywords

Type
Research Article
Copyright
Copyright © Materials Research Society 2007

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References

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