Influence of the dysprosium ions on structure, magnetic characteristics and origin of the reflection losses in the Ni–Co spinels

Abstract The Dy-substituted Co1/2Ni1/2(Fe2-xDyx)O4 (0.00 ≤ x ≤ 0.08) spinels were obtained in nanosized form. Correlation between chemical composition, crystal structure, magnetic properties and electrodynamics properties was investigated. The features of the fine crystal structure were investigated using neutron powder diffraction. Magnetic properties were studied utilizing vibration sample magnetometry in the wide temperature and magnetic field ranges. Electrodynamic properties were measured in high-frequency range of 2–18 GHz using vector network analyser. This data was used for reflection losses calculations. There was observed high resonant reflection in the range of 2–6 GHz due to electromagnetic radiation absorption. The weakening of the reflected radiation was explained by the domain boundary resonance. This explanation correlates well with the data of the microstructure analysis. The nature of absorption due to domain boundary resonance in low dimensional magnetic oxides was given. A strong correlation between the level of chemical substitution and amplitude-frequency characteristics for investigated Co1/2Ni1/2(Fe2-xDyx)O4 (0.00 ≤ x ≤ 0.08) spinels was detected.