Preparation And Characterization Of High Performance GMR Multilayers

The discovery of the giant magnetoresistance（GMR）effect in 1988 opened up the craze in the field of magnetic electronics and brought a significant change in the field of magnetic sensors.As the important components of magnetic field sensing,GMR sensors have the advantages of high sensitivity,good linearity,small size,excellent thermal stability and low power compared with the traditional AMR and HALL sensors,and become a hot research field in sensor technology.The spin-valve structure material as a multi-layer material for the preparation of GMR sensor has the advantages of low saturated field,good stability,high GMR effect,can produce excellent performance GMR sensor,in the field of research attention.In order to realize the GMR sensor with excellent characteristics,the spin-valve structure materials as the core part of the sensor are studied in this thesis.The main work is about the preparation of the spin-valve film material,the structural characteristics of the spin-valve material and the testing of the performance parameters research.In this thesis,the deposition rate of each target sputtering in the magnetron sputtering system is firstly calibrated.The deposition rate of each target material was obtained under specific sputtering power and sputtering pressure,which provided the basis for the subsequent growth and preparation of spin-valve material.Secondly,on the SiO₂ substrate,Ir Mn top pinning structure "buffer layer / free layer / non-magnetic isolation layer / pinned layer / antiferromagnetic layer / capping layer" was prepared by magnetron sputtering system.By comparing the types and thicknesses of the thin films in the structure,the magnetic resistance curve of the spin valve materials were measured by a strong magnetic probe station,the obtained data were analyzed and the most suitable material types and thicknesses of the layers were found,and the excellent spin valve material was prepared.Finally,we study the effect of the angle between the magnetic field and the easy-to-magnetize axis of the spin-valve on the MR curve of the spin valve during the measurement.This angle includes the angle between the magnetic field and the axis of easy magnetization of the material when the applied magnetic field is in the plane of the spin-valve material.And the applied magnetic field is located in a plane perpendicular to the plane of the spin-valve material,perpendicular to the axis of easy magnetization of the material.The curve data obtained in these two cases were processed and analyzed to study the angular characteristics between the magnetic field and the easy axis of spin valve.