[formula omitted] Mössbauer spectroscopic investigation of complex magnetic structures in Ga, Sc, and In substituted M-type hexagonal ferrites

Abstract

Investigation of preliminary evidence that Ga, Sc, and In influence the bulk and dynamic magnetic properties of hexagonal ferrites by means other than those supported in existing models has been undertaken. In [formula omitted] ([formula omitted] In) and [formula omitted] the predominant [formula omitted] sublattice exhibits a remarkable splitting into two distinct subpatterns, [formula omitted] and [formula omitted] At [formula omitted] hyperfine fields, [formula omitted] for [formula omitted] are 411, 408, and 405 kOe, respectively, and for [formula omitted] are 358, 339, and 311 kOe, respectively. The [formula omitted] hyperfine field values are virtually unchanged from that of the pure hexagonal ferrites and are independent of substitution level. Contrastingly, the abruptness of the drop in the [formula omitted] hyperfine field and its dependence on the nature of the substituting cation are remarkable. The relative intensity of the [formula omitted] component correlates with the concentration of nonmagnetic species on the [formula omitted] and [formula omitted] sites and with the magnetic anisotropy. Scandium seems to have a more profound influence on the magnetic structure and interactions than indium or gallium. Further, at technically significant substitution levels, [formula omitted] of the different sublattices exhibit broad and overlapping distributions of values far removed from their distinctiveness in the pure hexaferrites. Thus, the net magnetization of Ga, Sc, and In-doped hexaferrites results from a complex interplay of magnetic dilution on the [formula omitted] site, enhancement of the magnetization through substitutions on the [formula omitted] site, and a complex influence from the substitution-induced [formula omitted] sublattice. © 1999, American Institute of Physics. All rights reserved.