# Questions tagged [magnetic-moment]

The magnetic moment of a magnet is a quantity that determines the force that the magnet can exert on electric currents and the torque that a magnetic field will exert on it. A loop of electric current, a bar magnet, an electron, a molecule, and a planet all have magnetic moments.

302 questions
Filter by
Sorted by
Tagged with
1answer
2k views

### Why is Ampère's law violated if there are no fringe fields?

What's wrong in this diagram? The reason is this: magnetic field lines between the two poles of magnet are perfectly straight in the given diagram, which is not possible. Fringing effect of the ...
6answers
63k views

### Can magnetic fields be redirected and focused at one point?

I know that magnetic fields can be redirected, but... given a situation where you have static magnetic field over a large area, and you want to quickly change the magnetic field strength. Is it ...
8answers
10k views

### What is the electric field generated by a spinning magnet?

Consider a cylinder of permanently magnetized material, with uniform magnetization pointing along the cylindrical symmetry axis (the $z$-direction). The magnet is rotating about its cylindrical ...
3answers
811 views

### Paradox about the Stern-Gerlach experiment with $B=0$, $\nabla B\ne 0$

In a modern interpretation of the historical Stern-Gerlach experiment, a beam of neutral silver atoms, each with spin 1/2, was sent in the z direction through a nonuniform magnetic field having both a ...
1answer
481 views

0answers
1k views

### What is the Landé g factor?

What is the Landé g factor? I know that it gives the relation between magnetic moment and angular moment, but i wanted to know why are those magnitudes related to each other and why is the magnetic ...
2answers
12k views

### Is it possible to create only a magnetic wave?

I want to know if its possible to create only a magnetic field,which i can direct to a certain chosen object?
1answer
369 views

### Magnetic moment of uncharged particles

As we know that particles, only having charge, can have magnetic moment, then how particle like neutrino (having mass) can have magnetic moment? Don't bother about neutron because it has charge ...
1answer
2k views

### Relationship between nuclear spin and nuclear magnetic moment?

We know that nuclear magnetic moment can be expressed in terms of the expected value for nuclear spin as: $$\langle\mu\rangle =[g_lj+(g_s-g_l)\langle s_z\rangle]\frac{\mu_N}{\hbar}$$ (Cf. Krane), ...
2answers
424 views

### Intuition on Magnetic Dipoles and Magnetic Moment

1) Magnetic Moment in terms of magnetic poles: According to Wikipedia, " Magnetic poles always come in pairs, their forces partially cancel each other because while one pole pulls, the other repels. ...
1answer
2k views

### Why is the magnetic moment of a proton weaker than the electron?

I know that the nucleus of an atom does not contribute to the magnetization of an atom or material, and that the magnetic moments of protons are much weaker than electrons. Why is the magnetic moment ...
0answers
138 views

### Why is a particles magnetic moment proportional to its spin?

the magnetic moment of a particles is given by, m=kS, where k is a constant the gyromagnetic ratio but where does this equation come from, is it just from experiments?
0answers
6k views

### How to calculate the magnetic dipole moment of a bar magnet?

I want to calculate the force between two magnets. In a previous Phys.SE question, I was told that I needed to use the dipole-dipole interaction, but that equation depends on $m$, the magnetic dipole ...
1answer
12k views

### Force from solenoid

I'd like to approximate the force from a solenoid, or at the very least find a formula which is proportional to the force so that I can experimentally find the constant for my particular case. ...
3answers
2k views

### How neutrons interact if not through an electromagnetic interaction?

According to the question Do positively charged particles exchange photons? there was an answer Yes. Photons are the carriers for the electromagnetic force, regardless of the charges involved. ...
1answer
219 views

### When does $\nabla \times B =0$?

In my lab, I use electromagnets to apply a magnetic gradient force to lots of very small (superparamagnetic) nanoparticles embedded in an elastic medium. I believe that these can be treated as ...
2answers
372 views

### For the transition metals, how does counting the number of up-spins and down-spins still give you a non-integer magnetic moment?

The transition metals like Fe, Co and Ni have magnetic moments of 2.2, 1.7 and 0.6 Bohr magnetons, respectively. The band theory says that you get this when you calculate the density-of-states of the ...
4answers
3k views

### Why are the magnetic moment and the angular moment related?

Why are the magnetic moment and the angular moment related? I've always read everywhere that they are related but found nowhere a satisfactory explanation of the cause
1answer
233 views

### Is neutrino really a point (fundamental) particle?

Having a non-zero magnetic moment, was a proof for neutron to not to be fundamental particle. Now we have enough literature or research work over neutrinos that have proved that neutrinos, being a ...
1answer
614 views

### Why don't alpha particles have magnetic moments?

As I understand, particles such as the neutron, whilst having no external charge still possess a magnetic moment due to the underlying charges of its components. By that logic why does the alpha ...
2answers
171 views

### Why are materials magnetic?

I have trouble understanding why some materials are magnetic. What I know so far, is that electrons are the main reason. Every single electron has a magnetic moment, which is defined as the torque it ...
3answers
11k views

### Why does Earth behave like Natural Bar Magnet?

What is the reason for the Earth to behave like a bar magnet and have poles (North and South poles)?
2answers
894 views

### What is the physical significance of the Dipole Transformation of Maxwell's Equations?

The Question Given Maxwell's equations of the form \begin{align} \bar{\nabla}\times \bar{B} = \dfrac{4\pi}{c} \bar{J} + \partial_0 \bar{E} \\ \bar{\nabla}\times \bar{E} = -\partial_0 \bar{B} \\ \bar{...
2answers
1k views

### The Einstein–de Haas effect on a ferromagnetic coil which generates the external magnetic field

The Einstein–de Haas effect, if I understand it correctly, demonstrates a deep relationship between the intrinsic angular momentum (spin) and the magnetic moment of a particle; For this reason when a ...
1answer
143 views

### Why is the neutron magnetic moment negative?

I understand that the magnetic moment is due to the quarks, but specifically why is it negative? Is it due to the two down quarks or something?
2answers
122 views

### Special relativity constrains massless electric dipoles, but not massless magnetic dipoles?

Discussion in comments on the two questions linked below leaves me confused about the following point. We expect a magnetic or electric dipole to make a field that has some universal transformation ...
1answer
128 views

3answers
320 views

### If electrons aren't revolving around the nucleus, why do atoms have orbital magnetic moment?

In most introductory textbooks, the explanation of orbital magnetic moment is based on Bohr's model and electrons orbiting around the nuclues, which can be modeled as a current loop. For example, here....
3answers
283 views

### Curie temperature and magnetization?

If an ferromagnetic object is heated and reaches Tc the magnetization gradually drops as we get closer to Tc or it's a instant drop? Can I assume as I heat the object, the magnetization is weakening ...