Search

Antiferromagnetic magnetization dynamics is more effective than ferromagnetic magnetization; however, it is extremely complex. Rare earth (RE) ferrimagnets, on the other hand, have tunable magnetization with associated negative exchange interaction in sublattices. Here, we study different RE-Fe ferrimagnets while changing the RE-content. We obtain various magnetic properties like saturation magnetization MS, coercivity HC, magnetic anisotropy energy constant Ku, exchange coupling constant λ, and compensation temperature Tcomp for different RE compositions. We suggest that along with MS and HC, λ is another important parameter that is easy to measure and has information that is similar to that in the spin-orbit torque effective field and the canting angle. [ABSTRACT FROM AUTHOR]

It is commonly known that the coercivity (Hc) of the rare-earth/transition-metal (RE–TM) compound is tuned based on the varying RE content as compared to the TM component. The drawback of this approach is that the Hc changes are permanent. In this work, we investigate the coercivity behaviors of the GdFeCo/Hf/MgO heterostructure where the heavy metal Hf layer is inserted in the middle not only to convert charge current into spin current but also to prevent the oxygen diffusion effect. A strong geometry dependence of coercivity detected on Hall bar devices is attributed to the intrinsic properties of GdFeCo and elucidates that the oxidation issue from MgO on GdFeCo is prevented. By selecting a proper Gd content, we demonstrate that the coercivity can be altered flexibly in a wide range H c max / H c min ≈ 200 % via electric current. We develop a simple model to simulate the roles of Joule heating and spin–orbit torques in the novel behaviors of coercivity. It is verified that the excellent magnetic characteristics of GdFeCo are still preserved while manipulating coercivity by the electric current. Our findings broaden the new magnetic behaviors of RE–TM alloys, making them attractive for tunable magnetic anisotropy. [ABSTRACT FROM AUTHOR]