Gate Voltage Controlled Spin-dependent Transport Properties In (Zn,Co)O Diluted Magnetic Semiconductor

Electrons have two properties which are charge and spin,but the traditional electronic devices mainly utilize the charge degree of freedom of electrons rather than the spin freedom.It is possible to obtain more convenient,faster and more powerful microelectronic devices with the full use of spin of electrons.For example,spin degree of freedom have the advantages of relatively long decoherence time and low energy consumption.Therefore,the research of spintronic materials and devices related,explore of new artificial magnetoresistance structure and functional materials,have been the international research hotspot and one of the important research areas not only in the past years but in the future.From the point of material system,magnetic semiconductor film materials have the characteristics of both semiconductor materials and magnetic materials.At present,the most researched magnetic semiconductor is Mn doped GaAs,but it's Curie temperature?180k?is much lower than the room temperature,which restricts its application in life and industry.As a result,looking for materials with Curie temperature higher than the room temperature has become an important direction of spintronics research.From the view of application,traditional electronic devices is based on the electronic transport properties of semiconductors such as Si,which operate the freedom of electrons in semiconductors.Spintronic devices,including giant magnetoresistance?GMR?heads and magnetic storage devices,not only relate to the charge characteristics of electrons but also need to manipulate the spin degrees of freedom.With development,higher integration level and faster computing speed are proposed for spintronic devices,and adding external electric field is one of the methods to realize the requirements.In this context,we study the effect of gate voltage on the spin-dependent transport properties in?Zn,Co?O magnetic semiconductor,including electric field control of resistance and anomalous Hall effect.It has important value for the next generation of new spintronic devices.The main content of my work is as follows:1.We prepared single crystal Co-doped ZnO on?0001?Al₂O₃ substrate and then analyze its structure and magnetic properties.We find the sample has good single crystal structure with RHEED and XRD.With magnetic measurements,we found that the sample film which prepared under the low oxygen partial pressure has ferromagnetism at room temperature.2.Electrical transport properties are measured by Hall bar structure of ZnCoO thin film and a gate.The structure is patterned by UV exposure micromachining process.3.Using ionic liquid as electrolyte can greatly improve the breakdown voltage,so we can make a research in a wider range of electric field.By applying a gate voltage,we can realize the manipulation of carrier concentration in?ZnCo?O magnetic semiconductor.The spin-dependent transport properties including anomalous Hall effect and resistance can also be manipulated.