Low Saturation Magnetization Garnet Ferrite for Co-Sintering
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Solution Overview
Problem
The production of multilayer magnetic components for microwave applications faces challenges due to non-compatibility between ferrite and dielectric materials, leading to separation during sintering due to different shrinkage and thermal expansion coefficients, limiting the use of cosintering technology for complex components.
Innovation Solution
A ferrite material with very low saturation magnetization, characterized by a specific chemical formula, is used, which includes rare earth elements and aluminum, allowing for reduced sintering temperatures and compatibility with dielectrics and metals, enabling the production of high-performance co-sintered components like circulators with low magnetic losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional garnet-type ferrites are used for microwave components, then good magnetic properties are achieved, but sintering temperature must be very high (around 1500°C) making co-sintering with metals impossible
Solution Approach 1:
The patent modifies the chemical composition parameters of garnet-type ferrite by substituting iron with aluminum and incorporating specific rare earth elements (Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) in controlled amounts. This compositional parameter change enables the material to maintain good magnetic properties while reducing sintering temperature to below 1000°C, making co-sintering with metals feasible.
Solution Approach 2:
The patent creates a composite ferrite material combining conventional garnet-type ferrite base with aluminum substitution and rare earth element additions. This composite approach integrates multiple material functions: the garnet structure provides magnetic properties, aluminum substitution reduces sintering temperature, and rare earth elements fine-tune magnetic characteristics, achieving both low sintering temperature and good magnetic performance.
2Ease of manufacture
If ferrite and dielectric materials are assembled using conventional cosintering, then integration is achieved, but different shrinkage and thermal expansion coefficients cause separation during sintering
Solution Approach 1:
The patent modifies the thermal and mechanical parameters of ferrite material through compositional changes (aluminum substitution and rare earth element addition). These parameter changes adjust the thermal expansion coefficient and shrinkage characteristics of ferrite to better match dielectric materials, preventing separation during cosintering while maintaining manufacturing integration benefits.
3Loss of energy
If saturation magnetization is reduced to enable dielectric replacement, then magnetic losses decrease, but magnetic functionality is compromised
Solution Approach 1:
The patent precisely controls the saturation magnetization parameter by adjusting aluminum substitution level and rare earth element content. This parameter optimization reduces magnetic losses for low-loss applications while maintaining sufficient magnetic functionality (saturation magnetization around 0.2 Tesla) for microwave component operation, achieving a balanced compromise between loss reduction and functionality retention.
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 ferrite material with low saturation magnetization facilitates the production of high-performance microwave components with reduced magnetic losses, enabling their use in frequencies up to 20 GHz and allowing co-sintering with metals, thus overcoming the compatibility issues and achieving stable assembly without delamination.
Implementation Method 1
The association of garnet-type ferrites with such 'substituents' of dielectrics at low sintering temperature and metallizations, for example based on silver or gold, thus allows the production of high-performance co-sintered magnetic components, such as in particular circulators, in which the low-loss magnetic ferrite can typically exhibit a saturation magnetization of the order of 0.2 Tesla for operation at high frequencies (a few gigaHertz).
Implementation Method 2
be able to be sintered at low temperature, around 900°C, i.e. 600°C below the sintering temperature of conventional garnet-type ferrites, which allows them to be co-sintered with dielectrics and metals such as gold or silver
Data Source
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Figure 5a
AI summary
One subject of the invention is a ferrite material of garnet structure with very low saturation magnetization characterized in that it corresponds to the following chemical formula: YaTRbBib'FecAldlneCafCugZrhViCOjSikO12±γ with TR: a rare earth or a combination of rare earths and: -1 ≤ γ ≤ 1; 3 (a+b+b'+c+d+e) + 2 (f+g+j) + 4 (h+k) + 5i = 24±2γ 1 ≤ a ≤ 3.5; 0 ≤ b ≤ 1.5; 0 < b' ≤ 1; 4 ≤ c ≤ 5; 0 ≤ d ≤ 1.5; 0 ≤ e ≤ 0.8; 0 ≤ f ≤ 1; 0 < g < 0.05; 0 ≤ i ≤ 0.8; 0 ≤ j ≤ 0.5; 0 ≤ k ≤ 0.5; with b + d ≥ 1.2. Another subject of the invention is a component comprising said material of the invention and a magnetic ferrite material of garnet structure.