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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2A superconductor does this: the Meissner effect. – mike stone Feb 22 '19 at 16:28
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Superdiamagnetism ($\chi$ = -1) is a state that occurs in superconductors.
Normal diamagnetism arises when electron spins in a material are induced to oppose the direction of an applied field; but the electrons are confined within their atomic orbitals, so the response is limited.
Superdiamagnetism arises from the Meissner effect: the formation of screening currents which flow to oppose the applied field, these currents being persistent due to superconductivity. The currents flow without resistance, and grow to create a magnetic field which exactly opposes the applied field, resulting in zero net magnetic field within the superconductor.
The distance to which an applied field can penetrate below the surface of a superconductor is the London penetration depth. Inside the superconductor, $\chi$ is effectively -1.
Mark Beadles
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I was under the impression that diamagnets also had persistent induced current, since there is no resistance inside the orbitals. – Juan Perez Nov 26 '21 at 12:08