Investigation Of The Spin Electronic Source Of Carbon Nanotube Field Emission

It is well known that electron is carrier of charge as well as spin. Making use ofthe property of “spin” has realized technology revolution of information memory. In1997,The first spin electron devices such as GMR (Giant Magneto Resistance)magnetic head MRAM (Magnetic Random Access Memory) had been made, in2007,French scientist Albert nd German scientist Peter grunberg because of their found ofgiant magnetoresistance effect and was awarded the Nobel Prize in physics. As wellas the GMR sensors and spin transistors have made great development on basictheory and application technology. The theory and the application research ofspintronics is becoming the focus in the domain of current electron and informationscience and technology.The thesis mostly carried through the study on preparation, characterization andperformance of high quality spin polarized electrode, by which we could realize highdensity spin polarized current inpouring in spin electron device, and we could realizethe function of the spin electron device. Nowadays, the gain of spin polarizedelectrode mostly keeps eyes on the structure of TMR (Tunnel Magneto Resistance)magnetic multilayer film. Through TMR electrode electron bring spin polarization,and the degree of spin polarization has closely relation with TMR. The greater ofTMR, the higher of the degree of spin polarization. So the preparation of high TMRspin polarized electrode became the emphasis of the thesis. We prepared the spin polarized electrode by ion beam sputtering, such as Fe,Ni,and prepared insulating layer Al2O3by magnetron sputtering. The investigationshowed that the growth parameter such as growth time, ion beam energy hadimportant influence on the thickness of the sample. Through a series of experiments,we could accurately control the growth thickness of the film, and gain high qualityfilm in nm level.On this basis, we devised the structure of MTJ (Magnetic Tunneling Junctions)and confirmed specific structure parameter. We carried through lower temperatureand different magnetic field showed that the MTJ we prepared had obviously doublecoercive force phenomenon. Meanwhile, we have acquire a22.7percent TMR and8percent at room temperature. and the study showed that the quality of the middleinsulated layer was the key in successfully preparing MTJ, and comparativelysmooth interface and sample annealing in certain temperature could effectivelyimprove the performance of MTJ.Since then, the Carbon nanotubes were prepared by thermal CVD method(Carbon Nano Tubes), and using screen printing method in the preparation of CNTson the surface of the MTJ that have obtained. Silk screen printing method of carbonnanotube field emission electron source won’t destroy the spin electrodes, but due tothe tubes orientation and distribution of printing method is random, so sometransport mechanism still need to continue to study, this study finally used in silkscreen printing of the carbon nanotubes prepared by the spin field emission electronsource the original rational device.