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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Magnetic moment produced by a charge in translatory motion (with no orbital motion)

A moving charge produces a magnetic field, while its magnetic moment is given by $$\mu = -g\frac{q}{2m}\textbf{L}$$ where, $g$ = gyromagnetic ratio, $q$ = charge, $m$ = mass, L = orbital angular ...
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Why Is an Inhomogenous Magnetic Field Used in the Stern Gerlach Experiment?

The apparatus used in the Stern Gerlach experiment is somewhat like the one shown below with magnetic pole pieces of different shapes producing an inhomogeneous magnetic field. But what would have ...
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Crystal electric field effects on spin-orbit coupling

Can someone highlight in general the correlation between crystal-electric-field, spin-orbit coupling in case of 3d7 ions under tetrahedral crystal field environment and their mutual effects on ...
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Angular momentum and magnetic moment [duplicate]

I have just started studying MRI physics and was reading F.Bloch’s paper on Nuclear Induction. https://doi.org/10.1103/PhysRev.70.460 In page 463, it is mentioned, To obtain this variation does not ...
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Vector potential inside and outside an uniformly charged rotating sphere of radius $a$ [closed]

A sphere a radius $a$ has a uniform charge density $\sigma$. This sphere is rotating around the $z$ axis at a constant angular velocity $\omega$. We are asked to check the vector potential $\vec{A}$ ...
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Can the electron's magnetic moment be considered as an electric moment?

The electron is known to have an intrinsic magnetic moment, where a magnetic moment is generally defined as "the magnetic strength and orientation of a magnet or other object that produces a ...
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What are the equations to describe the flip of magnetic moment of a permanent magnet due to external magnetic field?

If we push a much smaller magnet with larger magnetization toward a larger one with same pole facing each other.(S-S or N-N) Repulsion increases as we move forward, but when it is close enough for the ...
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How is the magnetic field zero when the magnetic dipole moment is zero?

So, my teacher was trying to explain me about Diamagnetic substances and he said that : Suppose the atom of an element has 4 electrons revolving around the nucleus in 4 different orbits. The ...
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Magnetized Sphere

I'm trying to solve the magnetostatic problem of a magnetized sphere using the expansion of $\frac{1}{|\textbf{r}-\textbf{r}'|}$ in terms of Legrendre polynomials. For simplicity I assume $\textbf{M}\...
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Is it possible to align a magnetic dipole completely in the direction of field?

considering $L$ is always greater than $L_z$ i.e angle between angular momentum/magnetic moment and magnetic field/z direction cannot be zero. Means $B$ and magnetic moment cannot be in same ...
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Explaining rest electron magnetic field through Special Relativity

I was reading this post. It says that the electron produces a magnetic field due to its internal magnetic dipole which is given by $$ {\boldsymbol \mu}= \frac{eg}{2m} {\bf S} $$ In Purcell's book, he ...
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How much of a “magnetic B field” can be expelled or shielded by a spherical superconductor or mu-metal sphere?

In a standard average 4 inch square magnet, What is the value of the Magnetic B field vector at a specified moment in time for such a magnet? Of that number, what is the direction of this particular “...
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Ampere's law: the position of amperian loop

Can Amperian loop be taken parallel to current. I.e suppose current is in a circular loop in xy plane. And let the screen you are watching is xy plane . Can we take amperian loop in the same plane. ...
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Why are small planar current loops of sufficiently small size interesting? (magnetic moments)

In the book Basic Laws of Electromagnetism by Igor Irodov, He introduces force on a closed current-carrying loop as; $$ F = \oint I \vec{dl} \times \vec{B}$$ And then he states the most interesting ...
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Is magnetic dipole moment the same as electric dipole moment?

In the problem below, why does the second method used to calculate magnetic dipole moment $\vec {\mu}$ essentially use the definition of the electric dipole moment $\vec {p}$? Is magnetic dipole ...
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How is magnetic moment of a surface current defined?

For current loops the definition of magnetic moment is $\textbf{m}=I\int d\textbf{S}$. But say I've a cube with a surface current, how can we define magnetic moment in this case?
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Deriving force acting on magnetic dipoles using the Lorentz force

I was always taught that classically all electromagnetic phenomena are encapsulated in the Maxwell equations and the Lorentz force formula for point charges: $$ \vec{F} = q\left(\vec{E}+\vec{v} \times ...
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Why for a magnetic vector potential $A=\frac{1}{2}B \times r$ is $r$ measured from the z axis, not from the origin?

This is an extract from Feynman. He is looking for various expressions for A to give a uniform B field along the z axis $B_0$ I have noticed that if we do take r to be the vector displacement from the ...
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Query about a protons magnetic moment precession during excitation in MRI

I am trying to learn more about the physics behind an MRI and am getting stuck trying to understand the process behind the excitation of the transverse component of the magnetisation. From what I ...
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Source of magnetic dipole potential energy

One of the basic expression that goes without much thinking is the potential energy expression of a magnetic dipole in a magnetic field, $$ U = -\mu\cdot B $$ In the case of electric and gravitational ...
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Einstein-de Haas Experiment

As my knowledge of the experiment goes: A long ferromagnetic sample is hanging vertically inside a solenoid. The solenoid provides a magnetic field which orients the magnetic moments of the magnetic ...
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Magnetic flux linked between two coils placed co-axially

I came across a scenario in which a coil having a radius $r$ is placed co axially to another coil having radius $R$. They have some non zero finite distance between their centers. If some finite ...
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Do the electron pair in an orbital, have a net orbital magnetic moment?

It has been made clear to me that 2 electrons in an orbital have opposite spins, and hence their spin magnetic moment nullify each other. But does the same happen with the Orbital magnetic dipole ...
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Magnetism in bipartite lattices

Suppose we have a bipartite lattice( A and B). By tuning some parameters in the Hamiltonian, we get a region of parameter space where sublattice magnetizations, $m_{A}$ and $m_{B}$ are both of same ...
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What is the definition of a spin-wave polarization?

In some literature, it seems that there is only the right circular polarized spin-wave in a ferromagnet. And there are left and right circular polarized spin-waves in an antiferromagnet in a square ...
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What does the metres squared represent in the dipole moment?

If I were to do an experiment measuring the magnetic field strength (in tesla) of an iron core solenoid magnet, how would I determine the value for the dipole moment in the formula displayed in https:/...
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Why does the loop expand?

My textbook had an example question: "A loop of irregular shape carrying current is located in an external magnetic field. If the wire is flexible, why does it change to a circular shape?" ...
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If a ferromagnetic material is magnetized and demagnetized enough times, will it become paramagnetic?

I know that heating a ferromagnetic material above its Curie temperature will make the material lose its ferromagnetic properties. If a ferromagnetic material is repeatedly magnetized and demagnetized ...
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When does Pauli and when does Langevin paramagnetism occur in a solid?

Pauli paramagnetism occurs in a free electron gas of spins. Langevin paramagentism occurs when one has distinct atoms with a non-vanishing total angular momentum, that is a unfilled outer shell. But ...
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What is the difference between Larmor diamagnetism and Landau diamagnetism?

I have a rough idea, but would like a more precise distinction.
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Relation between drift velocity and area velocity

Is there any relation between drift velocity and area velocity? And how I can to find area velocity for electrons in a magnetic field?
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Motion of charge particle in oblique magnetic field

When velocity of charge particle is neither parallel nor perpendicular to magnetic field, it follows a helical path (in uniform magnetic field). But can someone explain the magnetic bottle concept? ...
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Effective magnetic moment

How could I calculate the effective magnetic moment of the alloy (Ni2MnGa) theoretically? I haven't seen any examples on the internet, only the basic spin formula. I study my material when it is ...
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Why don't the electrons in a paramagnetic material precess around an external field?

When a paramagnetic material is placed in a strong external magnetic field, then you'll find that the magnetic momenta of the electrons in the material will align to the field, causing a net magnetic ...
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Why does the Larmor precession frequency depend on $\vec{B}$ instead of $\vec{H}$?

From what I know: The magnetic field strength, $\vec{H}$, is the field generated by a free current flowing on an electric conductor. The magnetic flux density, $\vec{B}$, is a response of the medium ...
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Are electron spin axis and magnetic moment axis fully aligned?

It is known that the electrons behave in magn. moment detectors experiments at 45 degrees non classically but quantum mechanically where the amount of spin up and spin down electrons in percentage is ...
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Quick question regarding Larmor precession and bar magnets

So I was just reading a bit about magnetic dipole moments, Larmor precession, angular momentum etc., but there was one little thing that was bothering me. As far as I know, any angular momentum will ...
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How long does a material's magnetization take to align with an external field?

Take a ferromagnetic material which has been exposed to an external magnetic field $h_0$ for a long time and therefore has and equilibrium magnetization $m_0$. The external magnetic field then flips ...
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In the field of spintronics, what does it mean to change the order of an (anti) ferromagnet using torque?

I have been reading statements like "Ferromagnetic (anti-ferromagnetic) order can be detected or changed electrically using spin-transfer (spin-orbit) torque". What is the exact meaning of ...
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Where are current flowing in a permanent magnet?

We know that moving charges produce magnetic fields if then all elements have electron with some non zero angular momentum so all substances must be magnetic to some extend.But this does not happen. ...
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Magnetic field in a Tangent Galvanometer

I was reading about the tangent galvanometer online. I came across a youtube video : https://www.youtube.com/watch?v=wIuAnP9xfxw . It said that the field produced by the circular coil of the ...
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What is the correct definition of magnetic moment?

I found myself tired of by searching what is the exact definition of magnetic moment. I have also come across two formulas for same quantity $\vec{M} = \vec{m} \times \vec{d}$ where $\vec{M}$ is the ...
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Why torque on current carrying circular loop in uniform magnetic field is differs from results of $\mu \times \vec{B}$ if we apply calculus method [closed]

We have a current carrying circular wire kept in uniform magnetic field $\vec{B}$, as shown, I tried to derive the torque $\vec{\tau}$ acting on it For 2 elemental parts on wire subtending angle $d\...
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Magnetic field inside a ferromagnetic material

Let us suppose that there is a block of a ferromagnetic material inside a very long ideal solenoid, the magnetic field lines inside are in a straight line perpendicular to the surface of the block at ...
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1answer
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Torque on Circular Current Loop in Uniform Magnetic Field [closed]

I am trying to derive the expression: $\tau=\mu\times B$, for a circular current loop in a uniform magnetic field. $\mu$ is the magnetic moment of the loop, so it will be $\mu=IA$, where A is the area ...
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Divergence of the magnetic field $H$

it is known (although I have not found much information about it on books and websites) that, while the divergence of $B$ is always zero ($\nabla\cdot B = 0$), we cannot say the same about $H$: the ...
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Gluon radiation from a nucleon?

Due to the fact that neutrons and protons consist of quarks (i.e. are not really Dirac particles), their magnetic moments differ from the so-called "nuclear magneton" (i.e. the natural unit ...
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Why does the tangential component of the magnetic field increases inside a material?

Let us suppose that there is a constant uniform magnetic field perpendicular to the surface of a block of iron. Why does the magnetic field increases inside the block? Is it due to the alignment of ...
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Magnetoelectric effect

I am trying to find a concise and clear paper/book/reference in which there is a proof of the fact that any chiral molecule shows magnetoelectric effect. Could someone help please?
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Does magnetism of metals increase when they are irradiated?

Metals have magnetic properties because they are crystal structures with unpaired electrons moving around through them, these unpaired electrons have a net spin. Does irradiating a metal increase the ...

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