Anisotropy of Fe3+ Ions in Yttrium Iron Garnet

Abstract

Using the single-ion theory of anisotropy, it is possible to derive the anisotropy constants at OaK for yttrium iron garnet in which the iron ions on tetrahedral and octahedral sites are replaced by nonmagnetic ions of gallium, indium, or scandium, respectively. The theoretical variation of KI has been compared with experimental values derived from torque measurements on single crystals of Y.Ga.Fe6-Z012 (x = 1.15), Y.ln.Fe.-z012 (x=0.12, 0.20, 0.49), Y.Sc.Fe6_z012 (x=0.87) between 1.5° and 300 0 K. Although the results of the tetrahedral substitution fit the sample theory, the results for octahedral substitution give values of KI much lower than predicted. These values can be explained by assuming that the octahedral substitutions modify the crystal-field parameters of the unsubstituted Fe H ions and thus alter their contribution to the over-all magnetocrystalline anisotropy.

Investigations of lanthanum doping on magnetic properties of nano cobalt ferrites

“…This means that in addition to the variation of M S , the magnetic anisotropy K does play a significant role in affecting the value of initial permeability, with an increase in the La 3+ ion concentration. Qualitatively, the variation of K can be explained on the basis of single ion anisotropy model [21], which shows that the Fe 3+ ions at the tetrahedral site are compensated by the negative anisotropy of Fe 3+ ions at the octahedral site. As the concentration of the La 3+ is increased, the cation distribution of Fe 3+ ions is modified.…”

Effect of In3+ ions doping on the structural and magnetic properties of Mg0.2Mn0.5Ni0.3InxFe2−xO4 spinel ferrites

“…3(f) that K 1 increases with increasing substitution of In 3 þ ions ( Table 5). Variations of K 1 can be qualitatively explained on basis of single ion anisotropy model [44], which shows that Fe 3 þ ions present at the A as well as B sites contribute to anisotropy energy. Net value of K 1 is given by relative contribution of positive anisotropy of Fe 3 þ ions at tetrahedral site, which is compensated by negative anisotropy of Fe 3 þ ions at octahedral site.…”

Structural and Magnetic Properties of Cr<sup>3+ </sup>Doped Mg Ferrites

“…The contributions to initial permeability arise due to domain wall displacement and domain rotation and are given by the expressions [29,30]. [31]. Fe 3+ ion occupying A site has a positive value of anisotropy constant while the other occupying B site has a negative value of it [32] and is twice as large as the positive value at A site.…”