Localized canting effect in Zn-substituted Ni ferrites

P. G. BERCOFF; H. R. BERTORELLO

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

Elsevier

Lugar: Amsterdam; Año: 2000 vol. 213 p. 56 - 62

0304-8853

A model of three sublattices (A, B and B’) to describe the magnetic behavior of mixed Ni-Zn ferrites is presented. It is proposed that only sublattice B’ is affected by canting, due to the substitution of Zn2+ ions in sublattice A. The cases where: (i) only Fe3+ ions are found in B’, and (ii) B’ is occupied by Fe3+ and Ni2+ ions are considered. The two-sublattice model with canting in sublattice B is presented for comparison with cases (i) and (ii). The canting angle qLis calculated from energetic considerations, assuming that the Jij ion-to-ion interaction energies are not modified by the substitution of Zn2+ ions in sublattice A. The number of Bohr magnetons per molecule, nB, and the Curie temperature, Tc, are predicted as a function of Zn content, z. The experimental values of nB as well as the results for Tc are satisfactorily reproduced by the model described in (i). Results on Zn-substituted Li ferrite are also mentioned. It is found that additional considerations on the interactions are needed for this system, as lithium acts as a non-magnetic dilution in the octahedral sublattice.