X-ray magnetic circular dichroism study of magnetic proximity effect in [Co/Gd/Pt]₁₀ Multilayers

The magnetic proximity effect (MPE), particularly the induced moment in heavy metal (HM) thin films in contact with magnetic films, is crucial for understanding magneto- and thermo-spin transport phenomena involving the interfaces of HM and magnetic layers, as well as for developing spintronic devices. While the MPE at HM/3d transition metal interfaces has been extensively studied, the induced moment due to rare earth magnets remains to be elucidated.

Here we report the investigation of induced Pt moment in specially designed [Co (0.5 nm)/Gd (1 nm)/Pt (1 nm)]₁₀ multilayers by X-ray magnetic circular dichroism (XMCD) spectroscopy. Temperature-dependent XMCD spectra at the Pt L_2,3, Co L_2,3, and Gd M_4,5 edges reveal Pt moments induced at both the Co/Pt and Gd/Pt interfaces, as the magnitude of the induced Pt magnetization follows the trend of Gd magnetization at temperatures below 70 K. Additionally, the induced Pt moments align with the direction of Co magnetization but are opposite to that of Gd magnetization. Our results highlight the significant MPE at Pt/rare earth Gd interfaces, which is an important consideration for spintronic heterostructure systems.