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