LOW MAGNETIC FIELD SENSING DEVICE

A NOVEL MAGNETIC FIELD SENSING DEVICE WHICH USES THE MAGNETIC STRAY FIELD FROM A NEEL WALL IN A SOFT (LOW COERCIVITY) MAGNETIC THIN FILM TO BIAS A GIANT MAGNETORESISTANCE RATIO (GMR) SENSOR LAYER, THEREBY PROVIDING A HIGH RESISTANCE CHANGE IN THE SENSOR LAYER WITH A LOW APPLIED FIELD IS BEING INVESTIGATED. PRECISE LITHOGRAPHY (<0.5 MUM) IS REQUIRED TO ETCH THE SENSOR LAYER TO THE PROPER WIDTH AND TO LOCATE THE SENSOR PROPERLY WITH RESPECT TO A DOMAIN WALL IN THE SOFT LAYER. TECHNIQUES TO CONTROL THE POSITION OF THE DOMAIN WALL WILL BE EXPLORED. A DEMONSTRATION DEVICE WILL DEMONSTRATE THE FEASIBILITY OF THE CONCEPT AND SHOW AT LEAST A 5 PERCENT CHANGE IN RESISTANCE FOR AN APPLIED FIELD OF 2 OE OR LESS. THIS DEMONSTRATION WILL ALSO CLEARLY SHOW THAT 10 PERCENT OR HIGHER MAGNETORESISTANCE IS FEASIBLE WITH LESS THAN ONE OE OF APPLIED FIELD.