STUDY OF MAGNETOELECTRONIC DEVICES BASED ON CO-HFO2 GRANULAR FILMS

Abstract

In this thesis two device structures based on Co-HfO2 granular films are implemented and discussed.

The first structure consists of inserting HfO2 layer in between the granular film. By controlling the roughness of the inserted layer, different types of transport are engineered. Thus the MR is moderated for current in plane devices (CIP). A simulation model based on Monte Carlo method is also implemented to augment the results. Current out of plane (CPP) devices are also studied and compared with their CIP counterparts. The CPP devices tend to show lower MR as compared to CIP devices because of the high field induced tunneling effect.

The second structure consists of inserting NiFe layer in between the granular film. This structure was studied to counter the high field induced tunneling in CPP devices discussed above. The NiFe layer acts as a flux enhancer and thus influences the MR. FEMM simulation modelling was used to understand and explain the flux distribution in such systems.