Magnetic Permeability: Temperature Effects

AI Thread Summary
Magnetic permeability in metals is not constant and varies with temperature, including at superconducting temperatures. The Meissner effect allows magnets to float due to induced currents creating opposing magnetic fields, but large reluctance limits this effect. The maximum reluctance is constrained by the permeability of free space unless relative permeability is artificially reduced. There is uncertainty about using the Meissner effect to generate electricity, particularly regarding the source of energy and the effectiveness of the opposing fields in semiconductors. Overall, the discussion highlights the complexities of magnetic permeability and its implications for superconductivity and energy generation.
Narayanan KR
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Is the superconductor in meissner effect able to completely repel external magnetic fields because it provides large magnetic reluctance(small permeability) thereby forcing the external flux to chose alternate paths of low reluctance as shown in case 1 electrical equivalent or is it because an equal and opposite field gets produced by current loops inside the superconductor(T<Tc) as shown by case 2 circuit
If it is case 2 then can this reaction field be harnessed by a coil for electricity ?
meissner1.jpg

One more thing i forgot to add, is magnetic permeability of a metal constant irrespective of its temperature including superconducting temperature ?
 
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The Meissner effect can make the magnet float, but the large reluctance seems unable to do this.

In addition, under the same size ratio, the maximum reluctance will be limited by the permeability of free space, unless we artificially reduce the relative permeability to less than 1.
 
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alan123hk said:
The Meissner effect can make the magnet float, but the large reluctance seems unable to do this.

In addition, under the same size ratio, the maximum reluctance will be limited by the permeability of free space, unless we artificially reduce the relative permeability to less than 1.
so the meissner effect is due to current loops followed by opposing magnetic fields created in the semiconductor ?
 
Narayanan KR said:
so the meissner effect is due to current loops followed by opposing magnetic fields created in the semiconductor ?
It seems that the situation is not far from what you said.

Narayanan KR said:
Can the coil use this reaction field to generate electricity?

In fact, I don't know much about how the Meissner effect works.
But if you want to use it to generate electricity, what do you think of its advantages and where the original energy comes from ?
 
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alan123hk said:
It seems that the situation is not far from what you said.
In fact, I don't know much about how the Meissner effect works.
But if you want to use it to generate electricity, what do you think of its advantages and where the original energy comes from ?
i guess the opposing field in the semiconductor is equal to external flux but never large enough to allow itself to be detected by a coil, it may have H but B=0
 
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