Noncollinear Magnetic Structures and Electrical Manipulation in Ferrimagnetic [Co/Gd]_N Multilayers

Noncollinear magnetic structures and minor loops in rare earth (RE)-transition metal (TM) ferrimagnet [Co/Gd]_N multilayers, which are investigated primarily using electrical transport methods. Noncollinear spin flop phases and minor loops appear near the compensation point under high magnetic fields. The minor loops are attributed to the flip of Co and perpendicular magnetic anisotropy (PMA). Variations in the anomalous Hall effect (AHE) loops are interpreted as changes in noncollinear magnetic structures. The effective magnetic field acting on Gd closely relates to the magnetization of Gd in both collinear and noncollinear phases, explained by molecular field theory and experimentally confirmed. An asymmetric spin flop critical field μ₀H_sf, resulting is observed from the PMA dominated by the magnetic anisotropy constant of Co moments K_Co. A magnetic structure phase diagram for [Co/Gd]_N multilayers across different temperatures and magnetic fields offers insights into the noncollinear magnetic structures of RE-TM ferrimagnets multilayers. Additionally, electrical manipulation of noncollinear spin flop magnetic structures is demonstrated, with spin orbit torque (SOT) being the primary cause for the shrinkage of minor loops induced by pulse current.