Tailoring ferrimagnetic properties using proximity effects in Co/Tb-Co bilayers

The magnetic properties of Co/Tb-Co bilayers are studied across a broad range of parameters (the thicknesses of the two layers and the composition of the alloy layer) using both experimental techniques and atomistic simulations. This work demonstrates the ability to precisely modify the compensation point of Tb-Co alloy thin films by adding a Co underlayer with a specified thickness. Furthermore, the range of parameters are identified for which the magnetization reversal of the alloy and Co layers occurs synchronously and provide a simple expression for calculating the effective composition of the bilayer system. Additionally, it is shown that an exchange-spring magnet behavior can emerge when the alloy is Tb-dominant and the Co underlayer thickness exceeds a critical threshold. It is also demonstrated that for Tb concentrations where the alloy layer is expected to be paramagnetic, the exchange coupling with the Co layer locally induces ferrimagnetic order near the interface, leading to a second transition back to Co dominance. This dataset includes: Magneto-optic measurements using P-MOKE magnetometer The results of atomistic simulation using the VAMPIRE package This work was supported by National Science Centre Poland under OPUS funding Grant No. 2020/39/B/ST5/01915 at the Institute of Molecular Physics of the Polish Academy of Sciences.