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 field earth, effect on bar magnet [on hold]

The magnetic moment of small magnet is 4.8 Am$^2$. It is kept in eanhs magnetic field in magnetic meridian with its north pole pointing towards geographical soudm. The neutral points are ...
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H field Vs B Field inside a magnet

I was studying electromagnetism and was going the basic definition and trying to understand their importance. I could not figure the difference between The H- Field and B- Field at first. So I ...
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Elliptical precession of magnetic moments due to external magnetic field

I have a magnet lying in the XY plane which happens to have an in plane Anistropy along +X. If I apply a field along +Z, the magnet, if initialized not along +Z, is expected to precess about +Z. ...
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How can diamagnetism levitate anything?

From the explanation of diamagnetism that I was given, the electrons when exposed to a changing magnetic field will change their spin in accordance to Lenz's law. This will induce an opposing magnetic ...
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What is Saturation Magnetization? and how to calculate it for given values of magnetic moment, lattice constant and Temperature

What is Saturation Magnetization? and how to calculate it for given values of magnetic moment, lattice constant and Temperature. I know that saturation magnetization is the state reached when , ...
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Is the magnetic dipole of the electron an intrinsic property?

The profound answer to the question How permanent magnets work? starts with Sub-atomic particles such as electrons, protons, and neutrons (and many others) have a fundamental quantity called a spin ...
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Particle deflection in a magnetic dipole field

Consider a small magnetic dipole of magnetic moment $\vec{\boldsymbol{\mu}} = (\mu_x, \; \mu_y, \; \mu_z)$ sitting at the origin. The magnetic field all around is \begin{equation}\tag{1} \mathbf{B} = ...
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Ferromagnetism and induced magnetism

According to Wikipedia: A magnetic domain is a region within a magnetic material where individual magnetic moments of the atoms are aligned with one another and point in the same direction thus ...
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What is $dB/dx$ where $B$ is magnetic field and $x$ is the separation between two magnetic dipoles?

I came across a question regarding the force between two magnetic dipoles $M_1$ and $M_2$ separated by a distance $x$ . Here in this text book I am given the solution is $$ B = \cfrac{\mu_0}{4 \pi}...
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Why is there no B-field parallel force on an electron orbiting a magnetic field line?

If an orbiting electron creates a toroidal magnetic field like a ring of current does, and this field is oriented opposite to the magnetic field line the electron is orbiting, then why is the electron ...
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How would a cloud of ortho-positronium atoms behave near a magnetic dipole?

The force on a macroscopic magnetic dipole with dipole moment $\mathbf{m}$ in an inhomogeneous magnetic field $\mathbf{B}(\mathbf{r})$ is given by $$\mathbf{F} =\nabla (\mathbf{m} \cdot \mathbf{B}(\...
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Calculate the force acting on a magnet inside a solenoid wrapped in Iron

Sounds like a simple question, doesn't it? But it isn't and it has been frustrating me to no end. First, my setup is fairly straightforward: I am building an electromagnetic actuator and have a magnet ...
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Can someone explain how magnetic potential energy can exist even though the field is non-conservative?

$U=-B\cdot \mu$ is defined to be the magnetic potential energy, I saw this in my lecture notes, but we had already talked about the fact that since the work done to move a charge there is path ...
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Beam separation distance of silver atoms in Stern gerlach experiment

The Sge experiment is well known and the principle is well understood. I am asked the question to find the distance $d$ between the 2 beams after they are separated at the end of the magnets in the in....
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Query about why there is a torque on this spinning ring in a magnetic field

We learnt in class that the $\vec m\times \vec B$ is the torque of a current loop in a magnetic field. I was trying to understand this by considering the diagram above. Let the B field be pointing in ...
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Partition Function of System of Atoms in a Magnetic Field

Problem: Consider a system of N atoms in a magnetic field $B$ pointing along the z-axis. Each atom has angular momentum J and the Hamitonian of each atom is $$H=-MB=-g\mu_B B\sum_i^N J_z^i$$ where $...
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The magnetic and electric dipole moment 'popping out' from multipole expansions

I interpret electric dipole moments and magnetic dipole moments as intrinsic properties of certain materials, but in Griffiths it's literally picked out of expressing the potential and magnetic vector ...
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Hysteresis in Magnetoresistance

I am measuring the magnetoresistance of a thin ferromagnetic film from -1T to 1T, it looks something like this - The magnetoresistance increases slightly between 0 and coercivity of the film and then ...
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Inconsistencies in finding magnetic vector potentials

Recently I've been studying for my electromagnetism finals and I reached a question about magnetic vector potentials. If I have a wire with constant current distribution, what is the magnetic vector ...
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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?
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Confusion regarding torque given by M×B

The magnetic torque acting on a loop of magnetic moment M placed in a magnetic field B, is given by τ=M×B. My question is, about which axis does this give the torque about? Is it the instantaneous ...
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Piezoelectric strain curves and magnetostrictive strain curves

I am trying to understand the differences in the strains produced in piezoelectric materials and magnetostrictive materials. Magnetostrictive materials will tend to strain the same way along the ...
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If electricity creates a magnetic field, could a (strong) magnetic field stop electricity? [closed]

Surely this would make the two magnetic fields interact and if movement was made impossible, the stronger magnetic field would block the weaker electromagnetic filed. Am I right (presuming that the ...
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Can $F=qvB$ be applied to a solenoid and a parallel moving magnet?

If you take a scenario like this, Charge gathers at either end, and if you could somehow form a complete circuit without there being a canceling effect, there would be a current flowing. This makes ...
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How a sphere can be assumed as dipole?

From the book introduction to electrodynamics by David Griffiths , fourth edition, page no 279, there is an example to find the magnetic field of uniformly magnetized sphere. It said the magnetic ...
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Applying method of images to magnetic dipoles

I want to apply the method of images to quasi-stationary calculate the 2D magnetic field distribution of a magnetic dipole and a half space with certain electrical properties (permeability, ...
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How is energy conserved in this case?

Consider a permanent magnet introducing a magnetic field at some fixed angle to a loop of wire on a spindle. If a fixed current is allowed to run through the wire, the lorentz force introduces a net ...
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Torque Generated by Magnetic Field [closed]

This is the solution that was given: I'm extremely confused how the solution is getting a magnetic field in the +y direction. I do the right hand rule and I'm getting a B into the board ...
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How to determine the best-fit magnetic dipole Gauss coefficient in a shifted coordinate system?

Introduction A planetary magnetic field $\vec{B}$ can be described outside of the planet using Gauss coefficients $g_n^m$ and $h_n^m$ and a spherical harmonic expansion: $$\vec{B} \;=\; -\vec{\...
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Is positive and negative magnetostriction attributed to the shape of the domains?

I have been reading up on magnetostriction, and noted that some materials expand while other contract in the direction of an applied magnetic field, and that it is attributed to the rotation of the ...
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Finding force from torque equation

I have read an article on electrostatics textbook that, $$\vec {F}= \nabla {\vec {\tau} }$$ Such as,the toraue equation on a magnetic dipole is $$ \vec\tau={\frac{{\mu}_0 m^2}{2\pi z^3} }\hat{z} $$ ...
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Why is the singularity not taken into account?

In this article "Reflections on Maxwell’s Treatise", Section 4.2, it says: He replaces $\mathbf{m}$ with a volume element of magnetization $\mathbf{M}\ dV$ , integrates over $V$ , and lets the same ...
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how much magnetic field is experienced at the centre of bar-magent?

What is the magnitude of magnetic field at the centre of bar magnet? What's its mathematical expression?
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Looking for an understanding of Toroidal Moments [duplicate]

The wikipedia page is not so enlightening Apparantly the Neutrino, if it is a Dirac particle, has a Toroidal Moment. Does this mean the Dirac neutrino would interact electromagnetically as well as ...
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Why does magnetic dipole moment $\vec{\mu}=\gamma \vec{L} $?

I have often seen that the relationship between magnetic dipole moment $\vec \mu$ and angular momentum $\vec{L}$ expressed as $$\vec{\mu}=\gamma \vec{L} $$ But consider a current loop of a charged ...
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Why do we think that the relation $\vec{\mu}_L=\frac{e}{2m_e}\vec{L}$ will be valid in quantum mechanics?

Assuming the electrons to revolve round the nucleus in circular orbits and using the fact from classical electromagnetism that a current loop behaves like a magnetic dipole of dipole moment $\vec{\mu}...
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Sine or cosine component of force on current carrying coil in a magnetic field

For calculating torque on a current carrying loop in a magnetic field, restoring torque that is, we use the $\tau=\vec{m} \times \vec{B}$ where $\vec{m}$ is the magnetic moment and $\vec{B}$ is the ...
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Can magnetic susceptibility χ be -1?

Is it practically possible that the magnetic susceptibility of a substance is -1? I thought so as such a substance could completely cancel the magnetic field, but I couldn't find anything as such.
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Is magnetic force relativistic effect or intrinsic property?

In this video, they explain that magnetic force is an effect of electric force due to special relativity. https://www.youtube.com/watch?v=1TKSfAkWWN0 But then, the same authors explain in this video ...
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Force on a magnetic dipole in an external magnetic field

I want to find an expression for the force acting upon a magnetic dipole with dipole moment $\mathbf{m}$ if that dipole is positioned in a stationary, external magnetic field $\mathbf{B}$. The ...
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Magnetic material demagnetization through Curie temperature

It is known that some materials lose their permanent magnetic properties when they are heated above certain temperature known as Curie temperature or Curie point. As those materials are cooled down to ...
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Parameters Affecting Demagnetisation

What parameters will affect how a ferromagnetic material is demagnetised? Assuming that only changing fields will induce demagnetisation (although I suppose I could well be wrong on that one), what ...
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Magnetic field around solenoid and toroid

Solenoid is proving a little bit confusing While getting through solenoid I found that the field outside it is extremely small and is negligible. Also the field at ends is half of that of center. ...
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Magnetic moment of a radially symmetric current

In my latest assignment I'm tasked with finding a magnetic moment $\mu$ of a hydrogen atom, whose current distribution $\mathbf{j}(\mathbf{r})$ looks like $$\mathbf{j}(\mathbf{r})=\frac{e\hbar}{3^8 \...
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Explanation for magnetic declination [closed]

A compass in New York points about 15 degrees west of true north; in California, it points about 15 degrees east of true north. Magnetic declination also varies with time. What are some possible ...
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Two questions about electron's magnetic spin

Does electron's magnetic spin mean that we can think of it as having the two magnetic poles? Does the spin mean that it generates magnetic field even if it is at rest? I expect to get 'no' to both ...
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How does the atomic magnetic moment get locked with external magnetic field?

When an atom has a net magnetic moment that is not aligned with external magnetic field, it is said that the atom rotates because of the torque and the magnetic moment gets aligned with external field....
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How much time does it take magnetization to appear, after turning on a magnetic field?

When a magnetic field ${\bf H}$ is turned on from zero, a piece of material, not previously magnetized, exhibits a magnetization ${\bf M}$ due to ${\bf H}$. According to ${\bf M} = \chi {\bf H}$, ...
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How do magnets move towards or away from each other?(Explanation on a molecular level)

Imagine two magnets on a horizontal surface, with two opposite poles facing each other. If one of them is north, then the other magnet with the south pole facing the north will move towards the north ...
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Are permanent magnets a relativistic effect?

The relationship between Electromagnetism and Special Relativity is something that always amazed me but I haven't fully understood yet. Misconceptions and contradictions seem to be widespreaded, and ...