Development of Giant Magnetoresistive Device with Perpendicular Magnetic Anisotropy

Abstract

<P>MAGNETORESISTIVE DEVICES WITH PERPENDICULAR MAGNETIC ANISOTROPY ARE INCREASINGLY BEING EXPLORED FOR FUTURE MEMORY APPLICATIONS. COMPARED TO THEIR IN-PLANE ANISOTROPY COUNTERPARTS, MAGNETOELECTRONIC DEVICES WITH PERPENDICULAR MAGNETISATION EXHIBIT IMPROVED THERMAL STABILITY, SCALABILITY AND HIGHER SPIN TRANSFER SWITCHING EFFICIENCIES FOR NANOSCALE MRAM DEVICES. IN THIS THESIS, THE DEPOSITION AND FABRICATION PROCESSES FOR MAGNETORESISTIVE DEVICES BASED ON CO/PD AND COFE/PD MULTILAYER STRUCTURES WERE OPTIMISED FOR BOTH PERPENDICULAR MAGNETIC ANISOTROPY AND MAGNETORESISTANCE. OPTIMISATION IN THE LAYER STRUCTURES ALLOWED THE DESIGN OF PERPENDICULAR DUAL SPIN VALVES TO ACHIEVE FOUR TUNEABLE AND DISTINCT RESISTANCE LEVELS FOR MULTI-STATE STORAGE APPLICATIONS. FOR SPIN TRANSFER SWITCHING EXPERIMENTS, A SELF-ALIGNED FABRICATION PROCESS FOR NANOSCALE CURRENT-PERPENDICULAR-TO-PLANE DEVICES WITH MINIMAL PROCESS STEPS WAS DEVELOPED FOR NANO-PILLARS DOWN TO 60 NM IN DIAMETER. FINALLY, THE REDUCTI