5 results about "Hexagonal ferrite" patented technology

The application discloses Y-type hexagonal ferrite material with dual magnetic heat effect and a preparation method and application thereof, belongs to the technical field of ferrite ceramic materials, and is denoted as Sr2Zn 2‑x Ni x Fe 12 O 22 (x=0.0, 0.8 or 2.0), and can be used as a heat sink composite material in the temperature range in which the inverse magnetic heat effect exists. For the Sr2Zn2Fe 12 O 22 material, a platform-shaped conventional magnetic heat effect exists near room temperature, is suitable for Ericsson magnetic refrigeration cycle, the magnetic entropy change and the relative refrigeration power gradually increase with the increase of the Ni ion doping amount, and reach the maximum when the doping amount is 0.8; under the condition that the magnetic field changes by 0-90kOe, the magnetic entropy change reaches 3.16J / kg K at 4K, -1.02J / kg K at 16K and 1.33J / kg K at 354K, and the corresponding relative refrigeration power is 358.68J / kg.

To provide a magnetoplumbite-type hexagonal ferrite magnetic powder having electromagnetic wave absorbing capability in a 50 to 70 GHz band including a 60 GHz band, and having a small change in peak frequency of transmission attenuation over a wide temperature range, and a method for producing the same, and to provide an electromagnetic wave absorber using the magnetic powder and a method for producing the same.SOLUTION: This invention relates to a magnetoplumbite-type hexagonal ferrite magnetic powder, wherein a metallic element satisfies the general formula: A(1-x)RExFe(n-y-z)AlyCoz, indicating an atomic ratio (in the formula, A is one or more selected from the group consisting of Sr, Ba and Ca; RE is one or more of rare earth elements; 0.05≤x≤0.70; 0.01≤y<1.00; 0.00≤z≤1.00; 11.00≤n≤12.50).SELECTED DRAWING: Figure 1

This invention provides a praseodymium-dysprosium co-doped M-type hexagonal ferrite material, its preparation method, and its application. The chemical formula of the praseodymium-dysprosium co-doped M-type hexagonal ferrite material is A. y Fe 12‑2x Pr x Dy x O 19 Where A is strontium and / or barium, 0.05≤x≤1, 0.9≤y≤1.4. This invention incorporates praseodymium and dysprosium into M-type hexagonal ferrite, reducing grain size and forming polyhedral aggregates. Simultaneously, praseodymium-dysprosium co-doping can form various impurity phases, creating interfaces between the impurity phases and the main phase, effectively promoting interfacial polarization. Furthermore, Pr... 3+ To Pr 4+ The conversion favors oxygen vacancies and Fe 2+ The formation of praseodymium-dysprosium co-doped M-type hexagonal ferrite material improves the dielectric properties and microwave absorption properties of the material. Furthermore, the praseodymium-dysprosium co-doped M-type hexagonal ferrite material provided by this invention has advantages such as tunable absorption frequency band, high absorption intensity, and high operating temperature, exhibiting stable absorption performance and can be used as a base material for other composite materials.

An effective and easily scaled-up chemical synthesis route to obtain L10 Iron-Nickel alloy from cyano / nitrosyl-metal complex precursor salts, for sustainable permanent magnets free of critical rare-earth elements, with a (BH)max ranging in between that 5 of hexaferrites (up tO~45 kJ / m3) and rare-earth-based permanent magnets (up to ~500 kJ / m3).

The application belongs to the technical field of ferrite material preparation, and specifically provides an X-band self-biased hexagonal gyromagnetic ferrite material based on Cr substitution and a preparation method thereof, so as to meet the engineering needs of X-band miniature integrated devices; the X-band self-biased hexagonal gyromagnetic ferrite material in the application comprises: a BaM hexagonal ferrite and an additive, wherein the chemical formula of the BaM hexagonal ferrite is BaCr x Fe 11.2‑x O 19‑δ , 0