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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.

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Ferromagnets - Permanent?

When researching about the Curie-Temperature and magnets in general, something got me confused. What is the difference between a ferromagnet and a permanent magnet? In a ferromagnet the spins are ...
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197 views

Does the electromagnetic force “split” at lower than normal energies?

Since we have working models for forces "combining" or being describable via a single framework at higher energies (such as the "electroweak" force and the aim of GUTs), does electromagnetism split ...
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The magnetic moments of Hadrons

So I am very confused about how to find the magnetic moment of a arbitrary hadron. I have found out that the magnetic moment of a quark is given by: $\mu_q = \frac{e_qM_p}{m_q}\mu_N$ Where: $e_q, ...
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Larmor Frequency for Spin Transition

http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/larmor.html Consider the process of Larmor precession of the magnetic moment associated with the spin angular momentum of an electron inside a ...
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Conservation of Angular Momentum in Einstein - de Haas effect

I am not really sure why the law of conservation of angular momentum should hold true in the Einstein - de Haas effect. Consider the following excerpt about the phenomenon (taken from Magnetism in ...
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Direction of torque due to magnetic moment

I have a problem with determining the direction of torque due to magnetic moment on a current loop. Since the torque is defined as $$ \tau = p_m \times B $$ so I guess the direction of the torque ...
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In quantum descriptions of atoms why are observables (which we derive from the wave function) attributed to electrons?

For example the orbital angular momentum, for the hydrogen atom. Is this the total angular momentum of the atom(electron and proton) or just the electron? I am asking because, I am learning about how ...
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Permanent Magnet Lines & Currents:

A permanent magnet produces lines of magnet flux that we call a "magnetic field". Those lines come from inside the magnet, come out of the N pole, loop outside the magnet, & return back into the ...
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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 ...
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Is the saturation magnetization of a thin film different if you apply the field at different directions?

I'm getting different values of the saturation magnetization when I measure them in-plane versus out of plane. The saturation magnetization for the out of plane measurement is greater than in the in ...
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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 ...
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Applying downward force on someone without adding to their weight

I am creating a scenario for a superhero comic, and need help with an idea. I'd like the solution to be based in scientific theory, or at least scientific fantasy, as opposed to resorting to simply ...
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Dipoles in an external rotating field?

Consider a bunch of magnetic dipoles in $x-y$ plane in an external magnetic field $B(t)=B_0 \hat{z}+B_1(\cos\omega t~\hat{x}+\sin\omega t~\hat{y})$. The dipoles are rotating around $z$ axis and of ...
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Why is it necessary to break symmetry to get magnetoelectric effect in multiferroics?

Spatial or time symmetry needs to be broken for both magnetic and electric to happen in the same material. But how is symmetry hindering the process?
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How would the frequency of particle spin be estimated if it really was rotation?

I understand from reading that particle spin is not real spin as the globe spins. from what I have read particle spin came about because of the magnetic field of a particle. If I understand the text ...
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How would one get the particle beam in Stern Gerlach experiment

How would I get a beam of silver atoms? I imagine this to be problematic, since the silver atoms are neutral. How would I accelerate them?
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Larmor Precession - What does precession actually mean?

Larmor Precession - What does precession actually means? Is it change in the orientation of the axis with which electron revolves around the orbit? But, shouldn't the radius of the orbit remain the ...
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Finding the magnetic moment of a permanent magnet to calculate the torque when exposed to a magnetic field

A permanent magnet has a magnetic moment $m$ associated with it. When exposed to a magnetic field $B$ the torque acting on the magnet can be calculated as $\tau = m \times B$. I am trying to ...
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If I double the amount of oxygen molecules, do I double the paramagnetic force?

Oxygen is well known to be paramagnetic. If I take one molecule, $O_2$, and measure its paramagnetic force due to externally applied magnetic field, and then add another molecule near the first ...
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Calculating Dipole Magnetic Moment Given Magnetic Field Strength [closed]

I am trying to figure out how to solve the following: The Earth's magnetic field can be represented, in a first approximation, by a magnetic dipole placed in the Earth's center, at least up to ...
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difference between magnetic dipole moment and torque on a magnetic dipole?

I am a bit confused. What is the difference between magnetic dipole moment and torque on a magnetic dipole ?
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Relation between magnetic moment and angular momentum — classic theory

How do I prove the relation between the vectors of magnetic moment $\vec\mu$ and angular momentum $\vec L$, $$\vec\mu=\gamma\vec L$$ ? Many text books and lecture notes about the principles of ...
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What is the volume magnetization of Fe3O4 (magnetite) monodomains at room temperature?

Magnetite is great stuff for making ferrofluids and has a huge amount of literature. Yet I can't seem to find an answer to the simple question in the title. The magnetization of various bulk ...
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Magnetic moment of an iron-core solenoid

I'm currently developing a Simulink model for the attitude control system (ACS) of an undergrad-developed CubeSat. The ACS uses magnetorquers for attitude actuation. The magnetorquers are iron-nickel ...
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Are the electrons spin and his magnetic dipole moment unambiguously connected?

Is the angle between the spin orientation and the magnetic dipole orientation for all electrons and under all circumstances the same?
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Repelling a weak permanent magnet with an electromagnet

I have a question about magnetic repulsion. Suppose I have a permanent magnet (axially magnetized) placed on top of the iron core of an electromagnet. I want to switch on the elctromagnet to repel the ...
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What is the physical significance of the Curie constant?

What is the physical significance of the Curie constant? I understand it depends on the effective moment of the ion and hence must be some measure of it, but what is it exactly? Like some average ...
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Finding the vector potential of an infinite cyclinder with uniform surface current

This is the second part of a problem in Griffith's "Introduction to Electrodynamics 4th Edition" (problem 6.16). The first part was to find the magnetic field inside a coaxial cable (2 concentric ...
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How to demagnetize a magnet temporarily?

How to demagnetize a magnet temporarily? Is it possible making a permanent magnet demagnetize for a short span of time? Or at least long time but temporarily!
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Is there a repulsive force between neutrons at all distances or just real close?

With particles of the same charge there is a repulsive force at all distances and physicists talk about neutrons repelling each other. Does this repulsion occur at all distances like with charges ...
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can magnet used in engines

My friend has told an idea that if the same poled magnets are placed in the motors instead of engines,it will produce the ultimate energy.because same poles are repelling each other. is it possible?
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Does the magnetic anisotropy state only have two possible directions?

Wikipedia says "The magnetic moment of magnetically anisotropic materials will tend to align with an easy axis". Does this mean that it is completely impossible to orient the magnetic moment with any ...
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241 views

Lifetime of the magnetization of a ferromagnet

In a ferromagnetic material, there's spontaneous magnetisation, meaning in the absence of a $\mathbf{B}$ field $\mathbf{M}\neq 0.$ This means that there may be different domains in the sample where ...
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How is energy conserved in a series of magnets, progressively moving another magnet upwards?

Imagine a tall building with windows allinged one above the other, and a railway going from the bottom of the building to the top of the building (vertically), right where the windows are. Imagine ...
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Ferro and Ferri magnetism

On which factors do the magnetic susceptibility of these type of materials depend? Id assume ferromagnets in general have higher susceptibility than ferrimagnets but is this true in all cases? For ...
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Unknown magnetic moment of orthohydrogen

Conforming to present atomic physics, the two elementary particles in hydrogen atoms can have either parallel or antiparallel magnetic moments, and the energy differences between these two kinds of ...
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Why toroid has no magnetic pole?

Our teacher taught us about Gauss law of magnetism, $\phi_B=\oint_s{\small{}}\vec {B} .\vec {ds}=0$(being valid because magnetic field line form closed loop, right?) which denies the existence of ...
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What will happen to a permanent magnet if we keep the same magnetic poles of two magnets close together for a long time?

What will happen to permanent magnet's magnetic field or magnetic ability if we keep same magnetic poles of two permanent magnet for long time? Will any magnetic loss happen over the long period of ...
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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)?
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717 views

Magnetic dipole and magnetic moment

I don't quite understand the meaning of these terms. My physics book just gives the mathematical definition of magnetic moment as $\mu=Ia$, which means nothing to me. I know it has to do with torque. ...
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673 views

Total magnetic moment in an atom

I have a doubt regarding the calculation of total angular momentum of electron in an atom. Which is the right way to do it? Method 1: Total magnetic moment $$ \begin{align} \vec{\mu_J} &= \vec{...
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How the neutron magnetic moment was measured?

How was the neutron magnetic moment measured? Was the antineutron magnetic moment measured too?
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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....
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Orientation of spontaneous magnetisation in cooling ferromagnet

I'm trying to understand the direction of magnetic moments in a ferromagnetic material after cooling down below it's Curie temperature. A permanent magnet of ferromagnetic material will loose it's ...
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592 views

Is the electron magnetic moment responsible for the Lorentz force?

My question about the sum of the electrons' magnetic moments in a wire(What is the sum of the electrons' magnetic moments in a wire?) had an answer which disappeared later. The answer was - if I ...
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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 ...
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342 views

Torque on wire summarized with magnetic moment

The magnetic moment of a current-carrying wire loop $L$ is $$ \boldsymbol\mu = \frac I2\oint_L\mathbf{r} \times \mathrm{d}\mathbf{r} $$ so the torque it experiences under a uniform magnetic field $\...
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How does a spinning electron produce a magnetic field?

I learned in my undergraduate physics class that atoms have magnetic fields produced by the orbit of electrons and the spin of electrons. I understand how an orbit can induce a magnetic field because ...
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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{...
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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. ...