Tagged Questions
2
votes
1answer
93 views
Does the electromagnetic field “spin”?
Due to electron "spin", a small magnetic field is produced. Maxwell's equations imply that magnetic fields are due to changes in electric fields. Is the magnetic field produced then because the ...
2
votes
1answer
81 views
two electron spins line up in opposite direction and the Ising model
What cofuses me with the Ising Model is the claim that these nearby little magnets want to face the same direction. facing the same direction, they have lower energy. This seems to conflict with the ...
2
votes
1answer
137 views
Does the expression of the orbital magnetic dipole moment have $c$?
The orbital magnetic dipole moment of a particle with mass $m$ and charge $q$ can be shown to be related to the orbital angular momentum through the equation
$$\displaystyle ...
2
votes
2answers
90 views
What are the specific electronic properties that make an atom ferromagnetic versus simply paramagnetic?
As I understand it, paramagnetism is similar in its short-term effect to ferromagnetism (spins of the electrons line up with the magnetic field, etc.), though apparently the effect is weaker. What is ...
21
votes
3answers
1k views
Why do we need 12 atoms to store 1 bit of data?
Recent research at IBM has found a way to store 1 bit of data in 12 atoms.
While that is a big accomplishment compared to what we have today, it does seem like a waste to a non-physics eye like me.
...
2
votes
1answer
415 views
Help understanding a Magnetic Levitation “Physics Toy”
I was shown a toy, yesterday, which I would like help understanding qualitatively.
A fellow engineer showed me a kit which included three main parts:
1.) A base (black box), approximately 4 ...
0
votes
1answer
144 views
How to apply Andreev reflection formalism to ferromagnet ,normal metal interface?
The traditional formalism for andreev reflection deals with what happens at normal metal, super conductor interface.http://en.wikipedia.org/wiki/Andreev_reflection
(i.e when an electron from normal ...
3
votes
3answers
2k views
Does a magnetic field arise from a moving charge or from its spin, or both?
I learned that a moving charge creates a magnetic field perpendicular to its direction of motion. I also learned that charged particles like electrons have spin and they also create a magnetic field ...
4
votes
1answer
254 views
Relationship between magnetic resonance linewidth and spin relaxation
First of all, what is the mathematical relationship between measured linewidth (usually in units of magnetic field) and spin relaxation time? I see papers talk about spin relaxation times in terms of ...
7
votes
2answers
326 views
Why is the ground state of the ferromagnetic tetrahedron threefold degenerate?
I'm preparing a presentation on Spin-Ice, but something's been bugging me for a while. On the Wikipedia page for Geometrical Frustration, it says the following about easy spins on a tetrahedron with ...
