Demagnetizing Field Explained - What is It & How?

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In summary, demagnetizing field is the term used to describe the effect of B, rather than H, in polarizing atoms in iron near the end of a magnet. This can cause a slight decrease in the magnetization of the magnet over time.
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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.
 
  • #3
I'll try to absorb what you said, and then come back.
Thanks for your post
 

1. What is a demagnetizing field?

A demagnetizing field is a magnetic field that is created when an object with a permanent magnetic field is placed within it. This field opposes the original magnetic field, causing it to weaken or disappear.

2. How does a demagnetizing field work?

A demagnetizing field works by creating a magnetic field that is opposite in direction to the original magnetic field. This causes the magnetic moments within the object to align in a different direction, ultimately weakening or canceling out the original magnetic field.

3. What are some common applications of demagnetizing fields?

Demagnetizing fields are commonly used in the manufacturing of electronic devices, such as hard drives and credit cards, to erase any previously recorded magnetic data. They are also used in the demagnetization of tools and equipment to prevent them from interfering with sensitive magnetic instruments.

4. Can a demagnetizing field be harmful?

In most cases, demagnetizing fields are not harmful to humans. However, they can interfere with the function of certain electronic medical devices, such as pacemakers, so caution should be taken in these situations.

5. How is a demagnetizing field measured?

A demagnetizing field is typically measured using a gaussmeter, which measures the strength and direction of a magnetic field. The strength of a demagnetizing field is typically expressed in units of gauss or tesla.

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