The basic mechanism by which certain materials (such as iron) form permanent magnets, or are attracted to magnets. Ferromagnetism manifests itself in the fact that a small externally imposed magnetic field can cause the magnetic domains to align and reinforce with each other, so that the material is said to be magnetized.
Questions tagged [ferromagnetism]
340 questions
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Do magnets lose some form of energy while attracting each other?
Consider two very strong magnets, one above a wooden table, one below a wooden table. As the two magenets clamp together, wedging the tableplate between them, at least the bottom magnet will experience a force that is stronger or equal to the…
salbeira
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How fast do the magnetic domains align with the external field?
Let say we bring a normal (not super strong) magnet near sort of an unmagnetized iron block.
1) Do the magnetic domains align instantly? Does it make any difference on magnetization strength if we keep the magnet there for a second or for a…
physicsguy19
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Question regarding Stoner excitation in ferromagnetic metals
So upon reading through "Quantum Theory of Magnetism" by Nolting and Ramakanth I saw the derivation of the Stoner excitations as spin flip excitations (in this case for free electrons) in which the excitation continuum looks like this:
which I…
goalgetter666
- 103
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What is the difference between Curie's law and Curie-Weiss law?
Curie's Law:
$$\chi_m = \frac{C}{T}$$
Curie-Weiss law:
$$\chi_m = \frac{C}{T-T_c}$$
(C is Curie constant and $T_c$ is Curie temperature.)
Vinay5101
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Why is the saturation magnetisation of a ferromagnet increased by lowering temperature?
I am referring to the B-H hysteresis curve of a ferromagnet under a cycled H field
I understand thermal disorder increases as higher temperatures, resulting in a transition to paramagnetism above the Curie temperature.
However, I expect at…
user5866
- 91
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How to find the Material of magnet
Is there any way to find out if a magnet is a neodymium, ferrite(ceramic), samarium cobalt or alnico magnet (based on color, texture, etc.)?
Shub
- 349
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Why is a manget's strength measured in Teslas when magnetic field strength decreases with distance?
I am currently studying magnetism as a part of AP Physics 2, and what confused me was that a Tesla was the unit for magnetic field strength(which decreases with distance) but it was also used to measure the strength of magnets. Why is this the case?…
Sagar Patil
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What is the Physical Process of Corrupting a Magnetic Key Card and Is There a Detectable Difference Between a Corrupted and Non-Corrupted Card?
I was just watching the BBC show Sherlock, S3E3: His Last Vow and I got to the part where John and Sherlock are breaking into the penthouse office. The technique Sherlock employs to get into the office is corrupting a standard magnetic keycard and…
Ulthran
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Why are austenitic stainless steels not ferromagnetic?
There has been a question about this from 2015 but I don't think it has been answered well enough and the question also wasn't specific so I'm hoping that this time around, someone will be able to give a more detailed explanation because I'm…
L.Kahling
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Is magnetic susceptibility infinite at Curie temperature for a ferromagnetic material?
By Curie-Weiss law , $$\chi_m = \frac{C}{T-T_c}$$ Where, C is Curie constant and $T_c$ is Curie temperature. If T = $T_c$ would then $\chi_m$ be $\infty$ ? But by theory , at Curie temperature the ferromagnetic material becomes paramagnetic. But ,…
Vinay5101
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Breaking a magnet
When a bar magnet is broken into 2 pieces, we know that the 2 new pieces also become bar magnets with 2 poles. The piece corresponding to the north pole of the unbroken magnet gets a new south pole, and likewise the other piece gets a new north…
QuasarChaser
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Temperature and remanent magnetization
Is it necessary or required to take into account the temperature of the environment whilst determining the remanent field $B_r$ of a magnet? According to the datasheet of the magnet $B_r$ is somewhere in between $1.29-1.32$ T and the maximum…
measurepvm
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Curie Weiss fit
I would like to know up to what point do we know our material is paramagnetic or not. I fitted a curie Weiss model in the linear region of my curves with different fields each and I am having positive and negative curie temperatures.
What does this…
TeenageWitch
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How is magnetic energy supplied, v. 2.0?
This is a follow-up question to my Physics SE question from yesterday:
How is magnetic energy supplied?
The kind responses were very informative, but I still have much to understand about magnetism, as follows:
Scenario:
Imagine a piece of iron…
Stu Smith
- 145
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Coercivity of pure iron
Coercivity of 99.8% pure iron is 1 oe but that of 99.95% pure iron is 0.05 oe.Why such difference while both have same retentivity?
Edit: I mean to say if both have same amount of residual magnetism after removal of magnetic field then shouldn't…
TheVariant
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