In a magnetic head, there is provided, in the gap, a superconducting material that has zero permeability and prevents {HEAD ~ the passage} of {TAIL ~ the magnetic field} in the gap 
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In a magnetic head , there is provided , in the gap , a superconducting material that has zero permeability and prevents { HEAD ~ the passage } of { TAIL ~ the magnetic field } in the gap
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH