Spin Injection Into Wide Bandgap Semiconductor Zno And The New Fms / Nm / Fms Heterojunction Spin Injection Analysis

Spintronics was established and developed in the last 20 years. Such a new field was based on magnetics, semiconductor, microelectronics, information technique and nano-technique etc. The transport properties of spin-polarized electron, which include spin-dependent scattering, spin relaxation, spin injection and spin accumulation, were researched widely in the mesoscopic scale. In this field, the charge and spin being two characteristics of electrons, were both used for the processing of information and data storage. Due to the advantage of high speed, high density, low expense and fast response, spintronic devices have attracted more and more attention of corporations and research groups.Efficient injection of the spin-polarized electrons into the semiconductors was a key step of realizing the spintronic devices. Schmidt et al. predicted theoretically that the current spin polarization and magnetoresistance were too weak to be detected in experiment due to the conductivity mismatch between the ferromagnetic metal and nonmagnetic semiconductor. It is impossible to realize the effective injection of the spin-polarized electrons from ferromagnetic metal to nonmagnetic semiconductor. The ideal spin injection sources were those kinds of spin polarized materials, whose impedances have to match with the corresponding semiconductors well, such as ferromagnetic semiconductor or half-metal whose spin polarization is near 100%.We prepared CoZnO ferromagnetic semiconductor with the alternating deposition of very thin ZnO layers and Co layers by magnetron sputtering. The microstructure, magnetism, and transport properties of the samples of CoZnO(d_ZnO=0.5nm) were studied systematically. The microstructure and composition were investigated by XRD and HETEM. The measured results show a hexagonal nanocrystal structure and no second Co cluster phase can be observed, and the composition is uniform on a large scale. The average size of the grains was 4-6nm.Magnetic measurement indicates that all samples are ferromagnetic. The sample of...