M-Type Hexaferrite Ceramic Composite for Low Magnetic Loss
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Solution Overview
Problem
Developing ferrite materials for high-frequency applications is challenging due to high magnetic loss at high frequencies, limiting their use in very high frequency, ultra high frequency, and gigahertz antenna applications, despite hexaferrites having high magnetocrystalline anisotropy and ferromagnetic resonance frequency.
Innovation Solution
An M-type hexaferrite comprising oxides of Me, Me', Me'', Co, Ti, and Fe, where Me is Ba, Sr, or Pb, Me' is Ti, Zr, or Ir, and Me'' is Mg or Ca, with a dielectric phase of Me''TiO3, allowing for tunable magnetic properties and reduced magnetic loss, achieved by incorporating a dielectric phase and modifying the magnetocrystalline anisotropy field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pure M-type hexaferrite is used, then the crystal structure is thermodynamically stable and production temperature is low (around 900°C), but the material shows low permeability and high magnetic loss due to high magnetocrystalline anisotropy
Solution Approach 1:
The patent creates a composite material by combining M-type hexaferrite particles with a dielectric material to form a ceramic composite. This composite structure allows the ferrite phase to provide magnetic properties while the dielectric phase reduces overall magnetic loss and improves permeability, resolving the contradiction between ease of manufacture and reliability in high-frequency applications
2Speed
If ferrite materials are used for high-frequency applications, then high magnetocrystalline anisotropy field and ferromagnetic resonance frequency are achieved, but high magnetic loss at high frequencies limits their use
Solution Approach 1:
The patent modifies the magnetic properties by changing the composition parameters - specifically incorporating cobalt substitution and forming a composite with dielectric material. These parameter changes reduce the magnetocrystalline anisotropy field while maintaining high resonance frequency, thereby reducing magnetic loss and enabling high-frequency applications
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The M-type hexaferrite exhibits high permeability, low magnetic loss tangent, and high resonance frequency, with a figure of merit enhanced by varying the ratio of magnetic and dielectric phases, enabling effective use in high-frequency applications such as antennas and filters.
Implementation Method 1
hexaferrites having high magnetocrystalline anisotropy and ferromagnetic resonance frequency
Implementation Method 2
a dielectric phase of Me''TiO3, allowing for tunable magnetic properties and reduced magnetic loss
Data Source
AI summary
In an aspect, an M-type ferrite, comprises oxides of Me, Me′, Me″, Co, Ti, and Fe; wherein Me is at least one of Ba, Sr, or Pb; Me′ is at least one of Ti, Zr, Ru, or Ir; and Me″ is at least one of Mg or Ca. In another aspect, a method of making an M-type ferrite comprises milling ferrite precursor compounds comprising oxides of at least Co, Fe, Ti, Me, Me′, and Me″, to form an oxide mixture; wherein Me comprises at least one of Ba, Sr, or Pb; Me′ is at least one of Ti, Zr, Ru, or Ir; and Me″ is at least one of Mg or Ca; and calcining the oxide mixture in an oxygen or air atmosphere to form the M-type ferrite.