Does the length of an iron bar changes when it is magnetised?

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The length of an iron bar can change when magnetized due to its magnetostrictive properties, which involve the alignment of its atomic structure in response to a magnetic field. This change in length is influenced by factors such as the bar's size, shape, and the strength of the magnetic field applied. The process of magnetization involves passing the iron through magnetic field lines, generating electrical currents that create heat and hysteresis. However, the resulting length change is often minimal and may be undetectable without precise instruments. Overall, while the theoretical basis for length change exists, practical observation may be challenging.
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Does the length of an iron bar changes when it is magnetised?
 
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Theoretically yes, because iron is a magnetostrictive ferromagnetic material. The experimental measurement of this variation depends on your setup (iron bar size&shape, magnetic field strength, etc.).
 
Clive,
That' okay but how CAN the length increase.
They are just aligning in the direction of magnetic field.
 
Let's see now. To magnetize iron you have to pass it through the field lines. Doing so generates an electrical current. Current meets resistance, generates heat, hysteresis. When you heat something what happens?
Mind you, with every day magnets, the effect could be so small that it would be undetectable without some veery precise instruments.
 
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...
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