Static and Dynamic Magnetic Properties of Polycrystalline Hexaferrites of the Ba2Ni2-xCuxFe12O22 System

Abstract

The paper presents the results of a study of the phase composition and the main static magnetic characteristics: saturation magnetization, residual magnetization and coercive force of polycrystalline ferroxplana type hexaferrites of the Ba2Ni2-xCuxFe12O22 (0 ≤ x ≤ 2.0) system. These materials have high magnetic permeability and are promising for use as substrates for magnetic antennas and radar absorbing materials. It is shown that thermograms of the initial permeability can be used to quickly assess the presence of impurity magnetic phases in complex oxide ferrimagnets. The permeability and permittivity spectra of textured and non-textured composite samples with the powder of the Ba2NiCuFe12O22 hexaferrite are measured in the microwave frequency range. The radar absorbing properties of the obtained composites are analyzed. It is shown that magnetic texturing leads to an increase in the operating frequency band of an absorber with RL < −10 dB from 6.1 GHz to 8.2 GHz and a deepening of the loss minimum from −21 dB to −27 dB.

Phase Transitions in Magneto-Electric Hexaferrites

“…Their preparation route entails the coexistence of different magnetic oxides, mainly because usually the temperature range leading to their formation is very narrow, as especially clearly manifested in the synthesis of the Y phase. Zhuravlev et al summarized their findings on the phase composition of samples from the Ba 2 Ni 2– x Cu x Fe 12 O 22 system synthesized by the classical ceramic technology. Pullar presented an extensive overview on the influence of the synthesis conditions of the classical ceramic technology on the production of the different hexaferrite types.…”