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