Study Of Tunneling Magnetoresistance In Organic Spintronic

Electron is a quantum mechanical object,which possesses not only charge, but also spin. Microelectronics based on the electronic charge and their transportation have been widely used in the 20th century. Electron and holes enrich the transport characters of semicoductor materials. However, electron is treated as the carrier of the charge and its spin is usually neglected. The discovery of GMR(giant magnetoresistance) and TMR(tunneling magnetoresistance) in metallic spin valves have revolutionized applications such as magnetic recording and memory, and then a new field—spin electronics (also called as"spintronics")emerged. Spintronics refers to the study of the role played by electron (and more generally nuclear) spin in solid state physics, and possible devices that specifically exploit spin properties instead of or in addition to charge degrees of freedom. For example, spin relaxation and spin transport in metals and semiconductors are of fundamental research interest not only for being basic solid state physics issues, but also for the already demonstrated potential these phenomena have in electronic technology. The designed spintronic devices take use of the charge and the spin of electrons together to carry information and store information, which may further enhance the electronic devices work speed and efficiency. The intrinsic nature of electronic spin suggests it could be used as the basic unit (qubit) for quantum computation and communication. Conventional spin valves have been widely used in computers since the mid 1990s. As such, the 2007 Nobel Prize in Physics has been awarded to AlbertFert (UniversitéParis-Sud, Orsay, France) and Peter Grünberg (Forschungszentrum Jülich, Germany) for the discovery of giant magnetoresistance (GMR).In this thesis, considering the Ferromagnetic/Polymer/Ferromagnetic trilayered structures, we calculated results about the tunneling magnetic resistance (TMR) of the sandwich structures based on the free electron model of Slonczewski and some reasonable hypothesises. Aslo, the TMR of Ferromagnetic/Polymer/Insulator/Ferromagnetic (FM/O/I/FM) multilayered structures with the variation of the thickness of organic layer in the case of higher and lower spin filter factor for the organic layer was calculated by using the free electron model of Slonczewski. Also, the influence of the insulator layer thickness on TMR was calculated. The large TMR can be achieved by choosing moderate spin filter factor and insulator layer thickness. It was also found that TMR increases with the increase of potential in organic layer. These calculated results will be possibly helpful in the organic spin injection,transport,detection and designing the new organic spintronic device.