Novel behaviors of coercivity in GdFeCo/Hf/MgO heterostructure

It is commonly known that the coercivity (H-c) 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 H-c 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 & nbsp;)asymptotic to 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.& nbsp;(C) 2022 Author(s).All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY)license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

This study investigates the coercivity behaviors of the GdFeCo/Hf/MgO heterostructure, where the Hf layer is inserted to convert charge current into spin current and prevent oxygen diffusion. The coercivity can be flexibly altered by selecting a proper Gd content via electric current.