Abstract
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 T̄B 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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References
L. Néel, Ann. Geophys. (C.N.R.S.) 5, 99 (1949)
F. Luis, E. del Barco, J.M. Hernandez, E. Remiro, J. Bartolome, J. Tejada, Phys. Rev. B 59, 11837 (1999)
T. Tsutaoka, J. Appl. Phys. 93, 2789 (2003)
R.E. Rosenweig, J. Magn. Magn. Mater. 252, 370 (2002)
R.D. Zysler, D. Fiorani, A.M. Testa, J. Magn. Magn. Mater. 224, 5 (2001)
Y.D. Zhang, J.I. Budnick, W.A. Hines, C.L. Chen, J.Q. Xiao, Appl. Phys. Lett. 72, 2053 (1998)
W. Luo, S.R. Nagel, T.F. Rosenbaum, R.E. Rosenweig, Phys. Rev. Lett. 67, 2721 (1991)
M. Hanson, C. Johansson, S. Mørup, Phys. Rev. Lett. 81, 735 (1998)
F. Luis, F. Petroff, J. Bartolomé, J. Phys.: Condens. Matter 16, 5109 (2004)
E.W. Gorter, Nature 165, 798 (1950)
A.P. Hammersley, S.O. Svenson, M. Hanfland, A.N. Fitch, D. Hauserman, High Press. Res. 14, 235 (1996)
B.D. Culity, Elements of X-ray Diffraction, 2nd edn. (Addison-Wesley, New York, 1978), pp. 101–102
E.W. Gorter, Philips Res. Rep. 9, 295 (1954)
S.A. Morrison, C.L. Cahill, E.E. Carpenter, S. Calvin, R. Swaminathan, M.E. McHenry, V.G. Harris, J. Appl. Phys. 95, 6392 (2004)
N. Ponpandian, A. Narayansamy, C.N. Chinnasamy, N. Sivakumar, J.M. Greneche, K. Chattopadhyay, K. Shinoda, B. Jeyadevan, K. Tohji, Appl. Phys. Lett. 86, 192510 (2005)
Y. Ichiyanagi, T. Uehashi, S. Yamada, Phys. Stat. Solidi 1, 3485 (2004)
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75.50.Bb; 75.50.Gg; 75.30.Et
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Elizalde Galindo, J., Adair, A., Botez, C. et al. Zn-doping effect on the energy barrier to magnetization reversal in superparamagnetic nickel ferrite nanoparticles. Appl. Phys. A 87, 743–747 (2007). https://doi.org/10.1007/s00339-007-3892-1
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DOI: https://doi.org/10.1007/s00339-007-3892-1