Design and Operation of Spin Valve Sensors

Abstract

Two types of patterned, unshielded Giant MagnetoResistance (GMR) spin valve sensors have been fabricated: Nano-layered NiFe/Co/Cu/Co/NiFe and simpler NiFe/Cu/Co spin valves. GMR values of 7.6% for AH = 10 Oe were measured for the nano-layered structures on coupons. Transfer curves in uniform fields were obtained and were in agreement with theoretical expectations. The sensors were highly linear and well biased. Optimum biasing of the free layer in the spin valve sensor has new features over that in AMR sensors. These were explored in shielded as well as unshielded spin valves using micromagnetic simulation. © 1994 IEEE