Magnetic domain wall dynamics studied by in-situ Lorentz microscopy with aid of custom-made Hall-effect sensor holder
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Summary
This summary is machine-generated.We developed a Hall-effect sensor holder for magnetic flux density measurements inside a transmission electron microscope (TEM). This tool enabled studying magnetic domain wall dynamics, revealing lamellar carbides as strong pinning sites.
Area Of Science
- Materials Science
- Condensed Matter Physics
- Magnetism
Background
- Understanding magnetic domain wall (DW) behavior is crucial for magnetic materials.
- In-situ characterization within a transmission electron microscope (TEM) offers unique insights.
- Quantifying magnetic fields generated by TEM components is essential for controlled experiments.
Purpose Of The Study
- To develop and validate a custom Hall-effect sensor holder for in-situ magnetic field measurement inside a TEM.
- To investigate the dynamics of magnetic domain walls in a ferritic-pearlitic steel under an externally applied magnetic field.
- To correlate experimental observations of DW behavior with micromagnetic simulations.
Main Methods
- Fabrication of a custom Hall-effect sensor holder for precise magnetic flux density measurements within a TEM.
- In-situ Lorentz microscopy to observe magnetic domain wall (DW) dynamics.
- Application of an external magnetic field using the TEM's objective lens.
- Dynamical micromagnetic simulations to model DW behavior.
Main Results
- The objective lens exhibits a nearly linear response, with near-zero field when switched off.
- Magnetic domain walls in the ferritic matrix perpendicular to lamellar carbides initiate movement around 10 mT.
- DWs within globular carbides disappear around 160 mT, with saturation near 210 mT.
- Lamellar carbides act as strong pinning sites, retaining DWs up to 288 mT.
- Micromagnetic simulations successfully reproduced the experimental observation of DW disappearance in globular carbides.
Conclusions
- The custom Hall-effect sensor holder is effective for in-situ magnetic field quantification in a TEM.
- Lamellar carbides in ferritic-pearlitic steel significantly impede magnetic domain wall motion.
- Micromagnetic simulations provide a reliable tool for interpreting experimental DW dynamics.
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