X-ray spectrum and Mössbauer study of nickel ferrites excited by aluminum and chromium ions

Conclusions

According to the data of x-ray diffraction analysis all of the samples obtained of complex alloyed ferrites are single-phase solid solutions with the structure of spinel.

The addition of the matrix of nickel ferrite of ions of aluminum and chromium leads to a significant increase in specific electrical resistance with a simultaneous decrease in the tangent of the angle of dielectric losses.

X-ray absorption spectroscopy detects a shift in the K-boundary of Fe in the direction of higher energies, indicating an increase in the valence of the iron ions.

The Al³⁺ and Cr³⁺ ions occupy exclusively octahedral positions, which is confirmed by the character in the change in the nuclear γ-resonance spectra and in the macromagnetic properties in alloying.

Mössbauer and resistometric investigations confirm the changes predicted from the x-ray spectra in the electron configuration of the iron ions forming the matrix of the ferrite (Fe²⁺ → Fe³⁺ transition).

The Ni-Al and Ni-Al-Cr systems of ferrites are of definite practical interest for selection of the searching for compositions with improved characteristics as magnetically soft ferrite materials.

The method of activation alloying may be used in controlling the properties of ferrites.