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