The Study Of Large Magnetoresistance Effect In Diode-enhanced ZnCoO Devices

With the continuous development of information technology,emerging industries such as artificial intelligence,cloud storage,and big data have begun to affect our lives.With the rise of these emerging industries,the performance of integrated circuit devices has increasingly become a key factor in determining the pace of growth of emerging industries.By improving the precision of lithography and reducing the size of devices,the computing performance of integrated circuit devices has been continuously improved and power consumption has been continuously reduced.However,as the level of integration continues to increase,the device's dimensions have approached its physical limits and Moore's Law is about to fail.In the post-Moore era,due to the unique technological advantages of spintronics,it has attracted widespread attention.Based on the basic principles of spintronics,scientists proposed new logic devices,such as spin logic devices and magnetic field-based logic devices,and realized reconfigurable logic operation functions using magnetoresistance effects.It can be seen that spintronics has important application prospects in the post-Moore era.It will break through the physical limitations of traditional semiconductor devices and develop next-generation computer systems to achieve high computing performance,high integration,and low power consumption of information storage.And computing provides new ideas.Due to the profound physical connotation of the magnetoresistance effect and its huge practical application and commercial value in the field of magnetic sensors and magnetic storage,it has been the focus of spintronics research.The American scientific community has concluded that the anisotropic magnetoresistance effect(AMR)has been a major basic research result in the field of condensed matter physics in the past century.The giant magnetoresistance effect is a result of major applications.This shows that the research and application of the magnetoresistance effect has made indelible contributions to the progress of human science and technology.With the giant magnetoresistance effect and the tunneling magnetoresistance effect,humans have created new magnetic read heads,which have greatly increased the information storage capacity of the disk under the same volume.We usually call the magnetoresistance effect of the phenomenon that the resistance value of a material changes with the change of the external magnetic field.Generally speaking,we define the magnetoresistance ratio 'as:MR = ?(H)-?(0)/?(0)×100%,where ?(H)is the resistivity of the material under the external magnetic field of H.p(0)is the resistivity of the material when the external magnetic field is zero.The magnetoresistance effect can occur in many magnetic and non-magnetic materials.According to different mechanisms,the magnetoresistance effect can be divided into normal magnetoresistance,anisotropic magnetoresistance,giant magnetoresistance,cog magnetoresistance,tunneling magnetoresistance,magnetoresistance effect in ferromagnetic semiconductors,and anomalies in nonmagnetic semiconductors.Magnetoresistance,spin Hall magnetoresistance,rectification magnetoresistance and so on.Recently,Professor Zhang Xiaozhong's group at Tsinghua University successfully used the diode nonlinear transmission characteristics and the Hall effect of semiconductor materials such as silicon,germanium,and gallium arsenide to realize a giant magnetoresistance.This kind of magnetoresistance can be called a diode-enhanced magnetoresistance effect.However,since the hall effect of the material is utilized,the magnetoresistance ratio decays particularly under a small magnetic field,and the low magnetic field sensitivity is not high.The authors further used Ta/CoFeB/MgO's anomalous Hall effect to achieve large magnetoresistance ratios and high low magnetic field sensitivities,but due to the smaller resistivity of magnetic multilayers,the operating current was approximately 10 mA,and the power It is very expensive.Based on the above considerations,we have proposed a diode-enhanced ZnCoO device that achieves high magnetoresistance and high magnetic field sensitivity at low operating currents.In addition,we have also established a quantitative theoretical model through which the experimentally observed results can be well interpreted and the performance of the device analyzed.This paper mainly includes the following contents:1.Giant magnetoresistance effect of diode-enhanced ZnCoO devices.A diode-enhanced ZnCoO device was fabricated by coupling the switching characteristics of a Zener diode and the negative magnetoresistance of a ZnCoO amorphous magnetic semiconductor film.The device has a high magnetoresistance of-6850%at 6T,a magnetoresistance of-875%at 0.04T,and an operating current of<0.5 mA.At the same time,the magnetic resistance ratio of the ZnCoO thin film is only-13%.Diode-enhanced ZnCoO devices have been analyzed to achieve a high magnetoresistance ratio.In this device,the diode is turned on and off so that the device exhibits high and low resistance.The magnetic field will change the resistivity of the ZnCoO magnetic semiconductor film,thereby affecting the potential distribution on the film,and ultimately affect the transition between the high and low resistance states,so as to achieve effective amplification of the material's intrinsic magnetoresistance.2.The influencing factors of the magnetoresistance effect of the device.The relationship between the magnetoresistance and the diode transport properties of diode-enhanced ZnCoO devices was investigated.Transform diodes with different voltage regulators and measure device properties.We find that the steepness of the I-V curves of different voltage regulator diodes will affect the magnetoresistance.The higher the reverse breakdown voltage,the steeper the ?-? curve of the diode,and the larger the magnetoresistance ratio of the diode-enhanced ZnCoO device.3.The establishment of theoretical models and the realization of Boolean logic functions.A theoretical model describing the transport properties of diode-enhanced ZnCoO devices was established.The model considers the resistivity and geometrical structure factors of ZnCoO thin films and treats the diodes as ideal diodes.According to this model.we can simulate the ZnCoO thin film in the diode conduction and turn off the situation of the distribution of the two situations,the volt-ampere characteristic curve(IV curve)and the device's magnetic resistance ratio,etc.,can be consistent with the experimental results.Based on the diode-enhanced ZnCoO device,we introduced two small magnets,one of which is a control bit,and the other is a data bit,constructing a magnetic field-based logic device,and implementing a complete Boolean logic operation.