Professor John Gregg

Abstract:

La0.7Sr0.3MnO3 polycrystalline manganite thin films were grown on silicon (Si) substrates covered by SiOx amorphous native oxide. Curie temperatures of about 325 K were achieved for 70-nm-thick films. Strong room temperature XMCD signal was detected indicating high spin polarization at the surface. Cross-sectional TEM images show sharp interface between SiOx and manganite without signature of chemical reaction at the interface. Unusual sharp splitting of the manganite film was observed: on the top of a transition layer characterized by low crystalline order, a magnetically robust layer is formed. © 2007 Elsevier B.V. All rights reserved.

Abstract:

The integration of spintronic elements with silicon technologies in order to produce active spintronic devices with both power gain and spin function that can store and process data. Schmehl and his colleagues have succeeded in making high quality materials with europium oxide, which shows excellent epitaxy on their silicon substrate and their conductivity may be readily and sensitively varied to suit the application. Spintronics uses thin slices of ferromagnetic materials as spin sources and detectors. The epitaxial growth on silicon shows that the interface chemistry problems have been eliminated and goes well for integration with conventional electronics. One most possible field for spintronics is to transferred-electron phenomena to generate a spin-Gunn effects by which spin-dependent negative resistance might be realizable.

Abstract:

A burgeoning trend in spin electronics is the development of spin-sensitive semiconductor devices. Implementing spin-polarized carriers in semiconductors expands potential device functionality by differentiating between up and down spin carriers in both the conduction and valence bands. This spin selectivity may be realized by using magnetic semiconductors or by employing external spin-selective ferromagnets to inject spin-polarized current into nonmagnetic semiconductors. As the length scales are reduced, ferromagnetic single electron devices become feasible.