- #1
MMS
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Hello everyone. I'm not entirely sure if this is the right section to post this question in but if it isn't, then I apologize.
I'm studying for a test in E&M and I've come across a topic that had me thinking and I'm not quite sure if the explanation I'm thinking of is entirely true.
Please note that I don't know quantum physics yet, so explaining the bigger picture of things is much preferable.
Say, I got a piece of ferromagnetic material. Now from what I've read and comprehended, it's basically made of a lot of domains and each domain contains billions of magnetic dipole moments that are aligned in different directions in each domain.
If I apply external magnetic field in some direction, then the domain that contains the magnetic dipole moments which are parallel to the magnetic field starts enlarging itself and its "neighbours" start changing their direction in the same one as the magnetic field so at the end of the process all of the magnetic dipole moments face in the same direction.
When turning off this external magnetic field, they stay "frozen" in that direction.
Now a couple of questions:
1. a) Is what I described above true (in the big picture)?
b) There were also a couple of lines concerning the fact that there are "preferable" directions in which the spins would align. I'd appreciate it if someone could explain that.
2. Is that how they pretty much make magnets? they take a piece of ferromagnetic material, they put it in an external magnetic field and then what happens is the process I described above, and it becomes a magnet.
Also, is the strength of each magnetic determined by how "good" the magnetic dipoles are aligned?
For example, a really strong magnet has most of its magnetic dipoles in the same direction and weaker magnets have more "messy" ones?
3. What happens if I applied no external magnetic field? What properties does the material have then?Thank you!
I'm studying for a test in E&M and I've come across a topic that had me thinking and I'm not quite sure if the explanation I'm thinking of is entirely true.
Please note that I don't know quantum physics yet, so explaining the bigger picture of things is much preferable.
Say, I got a piece of ferromagnetic material. Now from what I've read and comprehended, it's basically made of a lot of domains and each domain contains billions of magnetic dipole moments that are aligned in different directions in each domain.
If I apply external magnetic field in some direction, then the domain that contains the magnetic dipole moments which are parallel to the magnetic field starts enlarging itself and its "neighbours" start changing their direction in the same one as the magnetic field so at the end of the process all of the magnetic dipole moments face in the same direction.
When turning off this external magnetic field, they stay "frozen" in that direction.
Now a couple of questions:
1. a) Is what I described above true (in the big picture)?
b) There were also a couple of lines concerning the fact that there are "preferable" directions in which the spins would align. I'd appreciate it if someone could explain that.
2. Is that how they pretty much make magnets? they take a piece of ferromagnetic material, they put it in an external magnetic field and then what happens is the process I described above, and it becomes a magnet.
Also, is the strength of each magnetic determined by how "good" the magnetic dipoles are aligned?
For example, a really strong magnet has most of its magnetic dipoles in the same direction and weaker magnets have more "messy" ones?
3. What happens if I applied no external magnetic field? What properties does the material have then?Thank you!
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