Samples of polycrystalline yttrium-iron garnet synthesized using radiation-thermal sintering and ceramic processing have been studied by the Mossbauer spectroscopy method. The best decomposition of the Mossbauer spectroscopy spectra of the research objects, which is a simulation of the experimental spectrum with five sextets, has been selected. An additional fifth sextet is caused by Fe3+ ions, which are surrounded by oxygen vacancies leading to distortion of Fe-tetrahedra, which is reflected in an increase in the quadrupole splitting of Fe3+. An increase in the density of s-electrons on Fe ions in distorted tetrahedra has been found, resulting in a decrease in the isomeric chemical shift δ of Fe ions to a value close to the δ value for Fe4+ ions. It has been shown that the optimal crystal structure is realized in Y3Fe5O12 polycrystals when they are sintered for 40–60 min in the temperature range of 1350–1400°C by the radiation-thermal sintering method.

Features of the Magnetic Structure of Y 3 Fe 5 O 12 Polycrystals Synthesized by Radiation Thermal Sintering

The influence of treatment in corona discharge plasma on the magnetic properties of BaFe12O19 single- and polycrystalline ferrites, as well as structural-chemical transformations in their crystal lattices, are studied. The revealed dependence between structural-sensitive microscopic parameters and the duration of corona-discharge-plasma treatment indicates the manifestation of the corona-electret effect in BaFe12O19 single crystals.

Modifying the properties of ferrite materials with a hexagonal structure via treatment in corona discharge plasma

The influence of corona-discharge treatment on the physical properties and structural state of superdispersed magnetite particles is investigated. It is ascertained that corona-discharge treatment can lead to the formation of polymorphous modifications.

Influence of corona discharge on the characteristics of superdispersed magnetite particles

Experimental investigations of the influence of a corona discharge on magnetic properties and domain structure of iron garnet films are conducted. We show that changes in the physical properties of iron garnet films due to a corona discharge result from the injection of negative oxygen ions and the formation of an electret state.

V. Kh. Kostyuk

Papers

Effect of treatment in a corona discharge on the surface properties of iron garnet films