One of the magnetic layers may be {HEAD ~ a so called granular structure} in which {TAIL ~ a magnetic material} is dispersed 
One of the magnetic layers may be { HEAD ~ a so called granular structure } in which { TAIL ~ a magnetic material } is dispersed
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH