The sensor stack includes {HEAD ~ a free layer} that is biased by direct exchange coupling with {TAIL ~ a layer} of antiferromagnetic material  
The sensor stack includes { HEAD ~ a free layer } that is biased by direct exchange coupling with { TAIL ~ a layer } of antiferromagnetic material
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH