Magnetic Layer Domain Wall Transport for Fluids
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Solution Overview
Problem
Current methods for transporting magnetic fluids or particles using magnetic layers face challenges such as inefficient particle movement, particle aggregation, and unspecific attachment to substrates, particularly when dealing with biomolecules in biological environments, where existing technologies often require complex magnetic field sequences and are limited by particle size and flow resistance.
Innovation Solution
The method employs domain walls in a magnetic layer with asymmetric re-magnetization properties to trap and move magnetic fluids or particles using a magnetic stray field, avoiding heating issues and particle aggregation, and allows for controlled transport across multiple domains with defined velocities independent of particle size or fluid viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If macroscopic external coils and yokes are used to create inhomogeneous magnetic fields for particle transport, then particle transport capability is achieved, but device complexity and size increase
Solution Approach 1:
The patent replaces macroscopic mechanical magnetic field generation systems (coils and yokes) with a microscopic magnetic layer structure that generates magnetic fields through its domain wall patterns. This substitution dramatically simplifies the device architecture while maintaining particle transport functionality, as the magnetic layer integrates field generation directly into its structural design rather than requiring separate macroscopic components
Solution Approach 2:
The invention transitions from three-dimensional macroscopic coil structures to a two-dimensional magnetic layer with patterned domain walls. By confining the magnetic field generation to a thin planar structure with laterally varying magnetization, the system achieves particle transport in the lateral direction while reducing the vertical dimension of active components, thereby simplifying overall device complexity
2Manufacturing precision
If topographic magnetic patterns close to particle dimension are used, then single particle transport is achieved, but transport of biomolecules in living cells becomes too large
Solution Approach 1:
The patent creates local magnetic field gradients through laterally varying magnetization directions in different regions of the magnetic layer. By controlling the magnetization orientation in specific local areas (e.g., alternating perpendicular magnetization in adjacent regions), the system generates localized stray fields that can trap and transport particles of various sizes, including biomolecules, without requiring the entire structure to be scaled to particle dimensions
Solution Approach 2:
The invention changes the magnetization parameter (direction and magnitude) spatially across the magnetic layer to create variable magnetic field landscapes. By adjusting the magnetization orientation in different regions, the system can generate appropriate field gradients for transporting particles ranging from single molecules to larger biomolecular complexes, providing adaptability across multiple scales
3Speed
If conventional magnetic field sequences are used for particle transport, then particle movement is achieved, but particle aggregation and unspecific attachment occur
Solution Approach 1:
The patent introduces a magnetic layer with laterally varying magnetization as an intermediary between the external control field and the particles. This intermediary structure generates controlled stray fields that mediate particle transport through well-defined magnetic gradients, avoiding the harsh and uncontrolled field conditions that cause particle aggregation and unspecific attachment while maintaining effective transport capability
4Length of stationary object
If external fields are applied to transport particles across large distances, then transport distance is improved, but energy consumption and heating increase
Solution Approach 1:
The patent employs periodic reversal of magnetization direction in the magnetic layer to create oscillating stray fields that progressively transport particles across the substrate. By alternating the magnetization orientation between adjacent regions in a periodic sequence, the system achieves net particle displacement over large distances while using low-energy magnetic switching operations rather than continuous high-energy field application
Solution Approach 2:
The magnetic layer structure itself serves multiple functions: it generates the magnetic fields for transport, provides the spatial gradients needed for particle manipulation, and enables directional control through its patterned magnetization. This self-service architecture eliminates the need for separate macroscopic field generation systems, reducing overall energy consumption while achieving long-distance transport
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 enables efficient and controlled transport of magnetic particles and fluids across large distances with high velocities, avoiding particle clustering and unspecific attachment, suitable for biological applications and lab-on-a-chip systems, while maintaining sensitivity for magnetic detection.
Implementation Method 1
transporting a magnetic fluid or at least one magnetic particle with the help of a magnetic layer
Implementation Method 2
a magnetic layer with asymmetric re-magnetization properties to trap and move magnetic fluids or particles using a magnetic stray field
Implementation Method 3
magnetic layer with asymmetric re-magnetization properties to trap and move magnetic fluids or particles
Implementation Method 4
moving in a predetermined direction a domain wall that separates adjacent magnetic domains in a magnetic layer
Data Source
Figure 1a~1c
Figure 2a~2d
Figure 3
AI summary
A method of transporting a magnetic fluid (104) or at least one magnetic particle (509, 510). The method comprises the steps of: providing a magnetic layer (102) with an asymmetric re-magnetization property; placing the magnetic fluid (104) or the magnetic particle(s) (509, 510) in the vicinity of the magnetic layer (102) so that they can magnetically interact with the magnetic layer (102); and applying an external magnetic field.