Extremely Polysubstituted Magnetic Material Based on Magnetoplumbite with a Hexagonal Structure: Synthesis, Structure, Properties, Prospects

Abstract

Crystalline high-entropy single-phase products with a magnetoplumbite structure with grains in the μm range were obtained using solid-state sintering. The synthesis temperature was up to 1400 °C. The morphology, chemical composition, crystal structure, magnetic, and electrodynamic properties were studied and compared with pure barium hexaferrite BaFe12O19 matrix. The polysubstituted high-entropy single-phase product contains five doping elements at a high concentration level. According to the EDX data, the new compound has a formula of Ba(Fe6Ga1.25In1.17Ti1.21Cr1.22Co1.15)O19. The calculated cell parameter values were a = 5.9253(5) Å, c = 23.5257(22) Å, and V = 715.32(9) Å3. The increase in the unit cell for the substituted sample was expected due to the different ionic radius of Ti/In/Ga/Cr/Co compared with Fe3+. The electrodynamic measurements were performed. The dielectric and magnetic permeabilities were stable in the frequency range from 2 to 12 GHz. In this frequency range, the dielectric and magnetic losses were −0.2/0.2. Due to these electrodynamic parameters, this material can be used in the design of microwave strip devices.

High-Entropy Oxides: Advanced Research on Electrical Properties

“…It can be deduced that a high temperature is conducive to the synthesis and stability of HEOs. The Gibbs free energy of HEOs tends to be negative at high temperatures, usually around 1000 °C (900 °C [29]~1400 °C [30]). More interestingly, the effect of configuration entropy is even greater for oxides.…”

High Entropy Oxide Phases with Perovskite Structure

“…In [16] formation of a multicomponent oxide phase with a spinel structure was reported. Our group initiated studies on high entropy phases with magnetoplumbite structure [17][18][19].…”

Flux Single Crystal Growth of BaFe12−xTixO19 with Titanium Gradient

“…M-type hexaferrites with space group P6 3 /mmc have found applications in various fields of technology as hard magnetic materials for permanent magnets and magnetic composites, information storage devices, and magneto-optical devices [1,2]. The growth of doped hexaferrite single crystals and study of their properties was the subject of many works in our laboratory [3][4][5][6][7][8].…”

“…In recent years, hexaferrites are increasingly being used in millimeter and sub-terahertz frequency ranges. Such devices are, for example, tunable resonators [9], insulators [10], and radar absorbing coatings in which hexaferrites are used both in the form of films and bulk materials [7].…”