HIGHLY MAGNETORESISTIVE THIN FILM MULTILAYERS

THE OBJECTIVE OF THIS PROPOSED PROGRAM IS TO SYNTHESIZE A THIN FILM MULTILAYER COMPOSITE MATERIAL WITH A VERY LARGE MAGNETORESISTIVE EFFECT - UP TO TEN TIMES THE 2.5% MAGNETORESISTANCE RATIO OF PERMALLOY MATERIALS USED TODAY. A RECENT FRENCH PUBLICATION(1) DESCRIBED A COMPOSITE FECR MULTILAYER WITH 25% ROOM TEMPERATURE MAGNETORESISTIVE RATIO MADE BY MBE TECHNIQUES. THIS PROPOSED PROGRAM WILL BUILD ON THAT WORK, BUT WILL PROVIDE A SOFT MAGNETIC COMPOSITE MATERIAL WITH LOW MAGNETOSTRICTION AND TCR WHICH ARE ESSENTIAL FOR PRACTICAL APPLICATION. THE MULTILAYERS WILL BE SPUTTERED FOR FAST TURNAROUND, ALLOY COMPOSITION CONTROL, AND RAPID COMMERCIALIZATION. FIRST EXPERIMENTS WILL USE FECR MULTILAYERS (9-60A(O) THICK EACH LAYER). THEN SOFT NONMAGNETOSTRICTIVE ALLOYS, INCLUDING PERMALLOY, WILL BE SUBSTITUTED FOR FE. ALTERNATIVES TO CR WILL BE INVESTIGATED. THE RESULTING COMPOSITES WILL BE CHARACTERIZED FOR MAGNETORESISTIVE AND MAGNETIC PROPERTIES FROM 2(O)K TO 330(O)K. A MODEL EXPLAINING THE MAGNETORESISTANCE OF THE COMPOSITE MULTILAYERS IS AN IMPORTANT GOAL.