Conventional electronics and computer devices utilize the charge of the electron. Besides charge, electrons have a quantity known as spin. This has opened up a field known as spin electronics or 'spintronics'. The goal of spintronics is to use the two possible spin states of an electron. These states, commonly referred to as "spin up" or "spin down" are ideal to replace the "one" and the "zero" states that are used in conventional computer technology. Spintronics has the potential to reduce the size and increase the speed of computers and storage devices. To be practical, all components of spintronic devices must operate at room temperature. The focus of this research project is to study SnO2 doped with transition metals(TM). In order to be optimized for technological applications the mechanism of magnetism in these oxide semiconductors must be understood. This project will investigate the interplay between the magnetic and transport properties as the defect and dopant concentration are varied. The goal is to develop a device with demonstrable spin injection from the oxide into a metal or semiconductor at room temperature. This would be an important step forward in semiconductor spintronics. This collaboration between FAMU, a historically black university, and the Materials Research and Technology Center at FSU will address, in part, the national shortage of African-American Ph.D.'s in physics. The graduate students' training will be enhanced by exposure to the broad range of laboratory techniques available at both institutions.
The focus of this project is to study spin injection from films of SnO2 doped with transition metals (TM). It has been proposed that ferromagnetism in the relatively new class of dilute magnetic oxides (DMO) is due to magnetic polaron formation at defect sites. To verify this, it is vital to investigate the magnetic and transport properties as a function of defect and carrier concentrations. SnO2 has been used for years as a gas sensor due to the ease with which defects can be introduced. Thus SnO2:TM is particularly useful for investigating the correlation between the carrier concentration and magnetism, as the defect concentration can be varied during and after growth. Thin films of SnO2:TM will be grown by pulsed laser deposition with varying TM and defect quantity. The magnetic and transport properties will be studied in detail. Low temperature deposition techniques will be explored for growth on technologically significant substrates such as Si and GaAs. The goal is to develop a heterostructure with demonstrable spin injection from the DMO into a metal or semiconductor at room temperature. This would be an important step forward in semiconductor spintronics. This collaboration between FAMU, a historically black university, and the Materials Research and Technology Center (MARTECH) at FSU will address, in part, the national shortage of African-American Ph.D.'s in physics. The graduate students' training will be enhanced by exposure to the broad range of techniques available at both institutions.
