Iron-rhodium (FeRh) exhibits a first-order magnetic phase transition from an antiferromagnetic (AFM) to a ferromagnetic (FM) state near room temperature, making it a promising material for spintronic and phase-change applications. In this study, we investigate various approaches to optimize and modulate the magnetic and transport properties of FeRh thin films, especially focusing on longitudinal spin pumping in the magnetic transition using FeRh.

First, we examine the impact of optimized growth conditions on FeRh thin films, revealing that annealing time and sputtering power significantly influence the sharpness and temperature of the AFM-FM transition. Films grown under optimal conditions exhibit well-defined magnetic domain evolution and a maximized magnetization change, highlighting the crucial role of fabrication parameters.

Next, we report experimental evidence of longitudinal spin pumping in FeRh/NiFe bilayers. By employing current-induced phase transitions, we observe a spin current emission during the transition, which is significantly larger than conventional transverse spin pumping effects. This suggests the presence of quantum fluctuation-driven spin dynamics, highlighting FeRh as an ideal platform for studying quantum spin transport phenomena.