Spin Valve Gmr Study Of Isolator

In industrial control systems, communications and measurement systems, isolator is a widely used and very important electronic component, its role is to eliminate ground potential difference, and isolate destructive noise produced by transient events. All the time, Optical isolator is mainly used to isolate these destructive signal. Compared with optical isolator, the giant magnetoresistance isolator is paid more and more attention for its high integration, small size, high speed, low power consumption and many other advantages. This thesis is mainly focus on the design and simulation of the plane coil of the GMR isolator, deposition process of spin-valve thin films, production process and performance testing of GMR isolator these aspects to carry out the work.Firstly, the structure and the working principle of the GMR isolator are studied, and the magnetic field simulation of planar coil that is one of the important structure of GMR isolator, Based on the simulation results, the requirements of performance of spin valve thin film materials for the GMR isolator are determined.Secondly, according to the requirements of the GMR isolator for spin valve film materials, based on the basic structure of spin valve, NiFe/CoFe composite free layer is used, the effects of the thickness of NiFe, CoFe in composite free layer and the thickness of Cu of metal layer for performance of spin valve thin film materials are studied. After a number of optimization, the spin valve thin film material is obtained whose MR=2%, hysteresis Hc=15Oe, the basic pint is at H=3Oe, based on the materials, the effect of temperature processing for spin valve thin film is discussed, the failure temperature of spin valve thin film is obtained which is200℃.Finally, spin valve resistance element is designed and fabricated by the semiconductor processing process, the effect of element’s width and easy axis is researched, based on this, the layouts and technological process of GMR isolator are designed, some fabrication runs have been conducted, the GMR isolator samples we got have good Wheatstone bridge, and the output voltage of isolator is90mV, the data transfer rate is0.4Mbps.