Magnon Confinement in oxide heterostructures

Over the past 2 years, there have been some new developments in SOT based manipulation of magnets. Particularly, the role of epitaxy and atomically perfect interfaces with spin and/or orbital current enhanced oxides has been shown to significantly impact the spin-to-charge conversion (or vice versa). We are studying spin transport in artificially constructed heterostructures of the multiferroic La-BiFeO3 using a combination of NV imaging and spin Hall measurements. Electrostatic confinement of the ferroelectric order parameter leads to the formation of an antipolar phase, which is subsequently controllable with an electric field. In the polar phase, we have discovered the powerful role of magnon confinement as a pathway to enhance spin transport (and thus the spin-to-charge conversion efficiency) by over 100X. Furthermore, there is the emergence of an altermagnetic state in such a confined BFO layer, as evidenced by spin transport anisotropy measurements. This talk will discuss our understanding of these effects and the prospects for future work.