I How Does a Vibrating Sample Magnetometer Calculate Magnetic Moment?

AI Thread Summary
A Vibrating Sample Magnetometer (VSM) calculates magnetic moment by measuring the induced voltage in a coil as the sample oscillates in a magnetic field. The relationship between induced electromotive force (emf) and magnetic moment is derived from the equation emf = -dPhi/dt, where dPhi/dz is proportional to the magnetic moment. This proportionality is based on the assumption of small amplitude oscillations, leading to a linear dependence of magnetic flux on the displacement z. The discussion highlights confusion around this relationship and the mechanics of the VSM, which involves a vibrating sample creating a measurable signal in a stationary coil. Understanding these principles is crucial for accurate magnetic moment calculations using VSM technology.
no_einstein
Messages
2
Reaction score
0
TL;DR Summary
How do you find the change in flux with respect to position
In descriptions of a VSM, the induced voltage in a coil is shown to be emf = -dPhi/dt = - (dPhi/dz)(dz/dt). From here, everyone seem to jump to a solution of emf = 2*Pi*A*f*m*sin(2*Pi*f*t).
That makes some sense: in this case, you can define z = A*cos(2*Pi*f*t) so (dz/dt) = 2*Pi*A*f*sin(2*Pi*f*t). I'm confused why (dPhi/dz) turns out to be equal to or proportional to m (the magnetic moment). Is it an approximation that assumes a small amplitude of oscillation and so a linear dependence of the magnetic flux on z? I am having trouble picturing this. Can someone help?
 
Physics news on Phys.org
What is a "VSM"? Is it a rotating coil in a magnetic field?
 
vanhees71 said:
What is a "VSM"? Is it a rotating coil in a magnetic field?
I guess it's his Vibrating Sample Magnetometer -- a quick search of Google Images turns up this:

1666717336498.png


https://en.wikipedia.org/wiki/Vibrating-sample_magnetometer
 

Attachments

  • 1666717315037.png
    1666717315037.png
    4 KB · Views: 144
Thread 'Motional EMF in Faraday disc, co-rotating magnet axial mean flux'

Thread 'Motional EMF in Faraday disc, co-rotating magnet axial mean flux'

So here is the motional EMF formula. Now I understand the standard Faraday paradox that an axis symmetric field source (like a speaker motor ring magnet) has a magnetic field that is frame invariant under rotation around axis of symmetry. The field is static whether you rotate the magnet or not. So far so good. What puzzles me is this , there is a term average magnetic flux or "azimuthal mean" , this term describes the average magnetic field through the area swept by the rotating Faraday...
View full post »

Similar threads

I Numerical calculations of a railgun yielded disappointing results
Replies
4
Views
897
I How induction works within a coil (nuances of it)
Replies
6
Views
2K
Loop falling in a magnetic field
Replies
4
Views
2K
Lorentz force and induced electric field
Replies
6
Views
1K
Calculating magnetic field outside a solenoid
Replies
15
Views
1K
I Derivative of the retarded vector potential
Replies
1
Views
2K
Current induced on a coil by a changing magnetic flux in another coil
Replies
5
Views
3K
Interaction between a neutral atom and an external magnetic field
Replies
2
Views
2K
Maximum Angular Velocity of an Electric Motor
Replies
2
Views
4K
Calculating multiple magnitudes for induced electric field
Replies
1
Views
2K

Hot Threads

Recent Insights

Back
Top