Charge and spin transport in Nb-doped SrTiO₃ using Co/AlO_x spin injection contacts

The spin of an electron is its intrinsic magnetic property and could be used to realize memory and logic devices, much like the electron charge nowadays, but more energy efficient and with better functionality. To realize control over the electron spin is however challenging and requires material properties which are not all present in the most used semiconductor: silicon. The use of the electron spin to realize electronics is being referred to as spintronics.

The work in this thesis describes theory and experiments on the realization of electron spin injection and detection into the complex oxide semiconductor niobium doped strontium titanate (Nb:SrTiO3) . In this work we realize spin injection at room temperature into Nb:SrTiO3 and show that we can control several aspects of the spin state not previously realized in silicon. The most important ones are control of the spin lifetime and the direction of the injected spins by purely electrical means.

Although presently the timescale in which the spin state is retained in this material is too low for practical devices this might be increased by optimizing the materials purity. This work shows that Nb:SrTiO3 is an interesting material to explore electron spin effects while also holding promise for the realization of spintronic devices.

Dissertation: http://hdl.handle.net/11370/c396e2a5-0dfc-48bf-90d3-64bf21d54676