Cluster-glass behavior in ZnFe2O4 nanoparticles

H. WIDATALLAH, I. AL-OMARI, F. SIVES, M. B. STURLA, S. J. STEWART

Rio de Janeiro

Workshop; C9.1 Vlll Latin American Workshop on Magnetism, Magnetic Materials and their Applications; 2007

<!-- @page { size: 8.5in 11in; margin: 0.79in } P { margin-bottom: 0.08in } -->Several works have demonstrated that when normal spinel ferrite ZnFe2O4 becomes nanosized displays a non-equilibrium cation distribution amongst their tetrahedral (A) and octahedral (B) sites that alters its magnetism. To study more in detail the magnetic behaviour of nanosized zinc ferrites with different grain sizes and degree of inversion (0.2 to 0.4), we have performed static and dynamic magnetic measurements such as ZFC-FC magnetization within the 4.2 to 873 K range, hysteresis cycles, frecuency dependence of the linear AC susceptibility, the non-linear susceptibility, and relaxation measurements. We demonstrate that the observed glassy behaviour can be interpreted through the progressive blocking and freezing of the interacting magnetic clusters formed due to the random non-equilibrium distribution of cations. Further, the glassy character is more pronounced as the ferrite is more inverted, and this coincides with the grain size increment.