Terahertz Spin-to-Charge Conversion in Strontium Iridate-Based Magnetic Heterostructures

Oxide interfaces have enormous potential for future electronics with many applications, such as large spin Hall conductance, phase transitions, topological states, and superconductivity. However, previous investigations have predominantly focused on gigahertz frequencies; whilst the possibilities to fabricate devices operational at terahertz frequencies are demonstrated. A model solution is proposed employing 5d rare-earth, strontium iridate (SrIrO₃) heterostructure with cobalt (Co) ultrathin layers. Femtosecond lasers are used to photoexcite the spins in Co, which super diffuse into the SrIrO₃ layer to produce an ultrafast inverse spin Hall effect in sub-picosecond timescales. The devices exploit the external magnetic field and laser fluence to control the spin polarization from the Co layer and demonstrate a tailored spin Hall effect. These results thus pave paths for next-generation ultrafast oxide electronics offering possibilities for room temperature-based devices.