Core-Shell Nanoparticles for Magnetic Structures
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic materials used in electro-mechanical apparatus have limited saturation magnetization, which restricts the strength of the magnetic field produced, and existing methods fail to significantly improve this fundamental property beyond the Slater-Pauling limit.
Innovation Solution
A process and apparatus for forming magnetic structures by depositing magnetic nanoparticles with a core covered by a layer of metal into a matrix, where the core and matrix materials are different ferromagnetic materials, using techniques like Molecular Beam Epitaxy and gas-phase deposition to embed the nanoparticles, reducing aggregation and enhancing magnetization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If magnetic nanoparticles are deposited into a matrix to increase magnetization, then the magnetic moment per atom increases beyond the Slater-Pauling limit, but particle aggregation occurs which reduces the effectiveness of the magnetic structure
Solution Approach 1:
A non-magnetic metal layer is deposited as an intermediary between magnetic nanoparticle cores, preventing direct contact and aggregation while allowing the magnetic moments to align. This intermediate layer solves the contradiction by enabling high nanoparticle concentration (improving magnetic moment) while preventing aggregation (maintaining compositional stability).
Solution Approach 2:
The invention creates a composite magnetic structure consisting of magnetic nanoparticle cores coated with non-magnetic metal layers, embedded in a matrix material. This composite approach allows combining the high magnetization of nanoparticles with the aggregation-preventing properties of the non-magnetic coating and matrix, resolving the contradiction between achieving high magnetic moment and preventing aggregation.
2Power
If the concentration of magnetic nanoparticles is increased to enhance magnetic field strength, then saturation magnetization improves, but the particles aggregate and lose their individual magnetic properties
Solution Approach 1:
The non-magnetic metal coating acts as a spacer that allows high nanoparticle concentration (enhancing magnetic field strength) while preventing direct particle-particle interactions that would cause aggregation and loss of magnetic properties. The intermediary layer maintains reliable magnetic behavior even at high concentrations.
Solution Approach 2:
The invention changes the physical parameters of the nanoparticle system by introducing a non-magnetic coating layer, which alters the effective volume and spacing between particles. This parameter change allows achieving high magnetic field strength through increased nanoparticle concentration while maintaining magnetic property stability through prevented aggregation.
3Quantity of substance
If traditional Fe-Co alloys are used to achieve high magnetization, then the Slater-Pauling limit is reached, but no further improvement in saturation magnetization is possible
Solution Approach 1:
The invention segments the magnetic material into discrete nanoparticle units with high magnetic moments, rather than using bulk alloy structures. This segmentation allows achieving magnetization beyond the Slater-Pauling limit by utilizing the enhanced magnetic moment per atom in nanoparticle form, while the non-magnetic coating and matrix provide adaptability in composition and structure.
Solution Approach 2:
The composite structure of magnetic nanoparticle cores with non-magnetic metal coatings embedded in a matrix provides versatility that traditional Fe-Co alloys lack. This composite approach enables magnetization beyond the Slater-Pauling limit while allowing adjustment of particle size, concentration, and coating thickness to optimize performance for different 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
This approach increases the magnetic moment per atom beyond the Slater-Pauling limit, improving the efficiency of magnetic materials in applications like electric vehicles and wind turbines by embedding nanoparticles in a matrix, thereby enhancing the magnetic field strength without marked aggregation.
Implementation Method 1
causing an atomic beam of such magnetic particles to impinge upon the matrix as it forms, thereby depositing those magnetic particles onto the matrix as the matrix forms
Implementation Method 2
wherein at least one of the matrix material and the core is of ferromagnetic material and the core and the layer of metal are of different materials
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
The present invention relates to a process of and apparatus for forming a magnetic structure on a substrate (44) and also a magnetic structure formed by such a process and apparatus. The magnetic structure comprises a matrix in which magnetic particles are embedded. Apparatus (30) for forming the magnetic structure on the substrate (44) comprises a source of matrix material ( 32) which is operable to deposit the matrix material onto the substrate to thereby form the matrix. The apparatus (30) for forming the magnetic structure further comprises a source of magnetic particles (34) which is operable to deposit the magnetic particles onto the matrix as the matrix forms to thereby embed the magnetic particles in the matrix. Each magnetic particle comprises a core covered at least in part with a layer of metal, at least one of the matrix material and the core is of ferromagnetic material and the core and the layer of metal are of different materials.