Magnetic Flux Exclusion and Expulsion

Note that the expulsion and exclusion responses are equal for T close to Tc. This reversible region extends from Tr down to an irreversibility temperature T which is a function of the applied field, varying as (H )2/ (35). The lack of reversibility at temperatures below Tirr indicates pinning of the magnetic flux the 

If the entire body is superconducting, the Meissner fraction will be reduced due to flux pinning (40). How can one determine whether a low Meissner fraction is due to flux pinning and/or due to a sample problem like superconducting shells One approach 

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