Effect of Laser-Induced Heating of the Antiferromagnetic IrMn Layer on Generation of Terahertz Pulses in Co/WSe2-Based Spintronic Emitters

Abstract

Properties of spintronic terahertz generators based on the IrMn/Co/WSe₂ and Co/WSe₂ structures grown on sapphire substrates are investigated. It is demonstrated that the optical energy of the pump pulse plays a critical role in coercivity control and in generation of terahertz radiation by a structure with an antiferromagnetic IrMn layer. Analysis of terahertz loops of magnetic hysteresis obtained for pump energies ranging from 0.35 to 3.85 mJ/cm² has shown that laser-induced heating of IrMn up to temperatures above the blocking temperature is accompanied by an increase in spin injection from the Co layer into IrMn layer and a consequent increase in THz emission efficiency. The results show importance of further investigation of thermal laser-induced processes in antiferromagnetic-based spintronic emitters in the vicinity of critical temperatures, which is of great significance of further development of terahertz spintronic and photonic devices based on antiferromagnetic materials.