The trilayer sensor is biased by {HEAD ~ a back biasing magnet} positioned at {TAIL ~ the back end} of the stack 
positioned at
The trilayer sensor is biased by { HEAD ~ a back biasing magnet } positioned at { TAIL ~ the back end } of the stack
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH