QDev Seminar: Larysa Tryputen

Spin Transport for Spintronic Applications

We live in the era of information and social networks. Though enormous amount of information can already be generated and stored, the growing market demand for high-density, low power and high-speed data processing asks for fundamental research on new materials with unprecedented performances, novel experimental paradigms, and efficient and scalable data processing methods which can satisfy that demand.

Spintronic devices, systems that use the spin of electrons to transmit, process and store information, have a great potential for realizing next-generation computing using spin-based materials. However, few key challenges must be addressed, to implement these devices and make them an integral part of computing. More specifically, we need: 1) to further understand the mechanism of spin-dependent effects at the nanometer-scale: 2) to solve scalability problem, and 3) to overcome the most serious problem in modern electronics - energy dissipation.

In this talk, I will review the main distinctive features of these three challenges and suggest how they can be addressed. I will first introduce the phonon spectroscopy, that can act as in situ nanometer-scale probe to study spin transport in non-magnetic/ferromagnetic point contacts as well as phonon spectrum of superconductor-normal metal contacts. I will then present experimental results demonstrating the utility of the method to clarify the mechanism of spin-valve effect and role of low-frequency phonons in high-critical temperature of a two-energy-gaps magnesium diboride superconductor (MgB₂). Then I will demonstrate scaling and switching behaviour of magnetic tunnel junctions with perpendicular anisotropy with a structure of Ta/CoFeB/MgO/CoFeB/Ta (Mo) of diameters < 50 nm. Finally, I will conclude by demonstrating the formation, annihilation and dissociation of 360 degrees magnetic domain walls in nanowires.