Spin and Charge Transport in Graphene Based Devices

The present dissertation is comprehended in two main parts. The first part is focused on understanding the mechanisms behind spin current to charge current interconversion (i.e. the spin Hall angle), where the spin current is generated by means of spin pumping. The measurement of a positive spin Hall angle of magnitude 0.004 in Uranium is reported in Chapter 2. These results support the idea that the electronic configuration may be at least as important as the atomic number in governing spin Hall effects. In Chapter 3, the design of a spintronics device designed to interconvert charge and spin currents in CVD graphene is presented. The second part of the thesis is centered in the study of transport through single molecules with the use of three-terminal devices. The first evidence of a molecular double quantum dot is detailed in Chapter 5. The conclusions are supported by self-assembled monolayers (SAMs) and single-electron transistors (SETs) measurements. Using gold electrodes for SETs measurements has its disadvantages, two of the main ones being: the junctions are not stable at room temperature and it does not allow for transport measurements in the presence of light. Graphene electrodes, on the other hand, have been reported to be stable at temperatures above room temperature and have no absorption in the visible range. Along those lines, the development of a multilayer graphene-based SET is reported in Chapter 6. Finally, a new technique, based on CVD graphene transistors, that will allow three-terminal measurements on an STM is described in Chapter 7