Demagnetizing Field Explained - What is It & How?

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SUMMARY

The discussion clarifies the concept of the demagnetizing field in bar magnets, emphasizing that the term is misleading. It states that at the ends of a bar magnet, the magnetic field strength (B) is half of its value compared to the center, leading to a gradual loss of magnetization (M) over time. The relationship between the magnetic field intensity (H) and magnetization (M) is also highlighted, with H pointing in the opposite direction to M at the magnet's ends. This understanding is crucial for accurately interpreting magnetic behavior in materials.

PREREQUISITES
  • Understanding of magnetic fields and their components (H, B, M)
  • Basic knowledge of magnetization processes in ferromagnetic materials
  • Familiarity with boundary conditions in electromagnetism
  • Concept of magnetic field strength and its measurement
NEXT STEPS
  • Research the mathematical formulation of demagnetizing factors in ferromagnetic materials
  • Explore the impact of temperature on magnetization and demagnetizing fields
  • Learn about the applications of demagnetizing fields in magnetic storage devices
  • Investigate the role of demagnetizing fields in magnetic circuit design
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Physics students, electrical engineers, and materials scientists interested in magnetism and its applications in technology.

sokrates
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Can anybody enlighten me on what demagnetizing field is and how it comes to existence?
 
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At the end of a bar magnet, H points in the opposite direction to M and B. This is due to the boundary condition on H at the end of a magnet. In many books, this is called a
"demagnetizing field". That is a misnomer, because it is B and not H that acts to polarize the atoms in the iron. Since B near the end of the magnet is 1/2 its value at the middle, there is some tendency for the magnet to lose a bit of its magnetization (M) over time.
 
I'll try to absorb what you said, and then come back.
Thanks for your post
 

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