Interplay between magnetization compensation temperature and thickness in ferrimagnetic CoGd alloy films

In this study, we explore the interplay between magnetization compensation temperature (Tcom) and thickness in ferrimagnetic CoGd alloys. Temperature-dependent anomalous Hall effect shows that the thickness of CoGd alloys can cause a 160 K shift in Tcom. Element-mapping image measurements display that the concentration of CoGd alloys remains constant regardless of the thickness, while magnetic property measurements indicate that the saturation magnetization (Ms) decreases as the thickness increases. A microstructure constructed by non-coplanar spin is used to account for the modulation of Tcom and Ms with the thickness. Density functional theory offers a microscopic mechanism where the difference in exchange coupling strength between Gd-Co moments should be responsible for thickness-controlled Tcom. Our findings reveal potential opportunities for the use of RE-TM ferrimagnetic films in the development of energy efficient nonvolatile spintronic devices.