Magnetic symmetry of Tb and Co0.6Fe0.4 co-sputtered for applications in ultrafast spintronic and sensor technologies

A thin film of Tbx(Co0.4Fe0.6)1−x, with x ≅ 0.2, was synthesized using magnetron DC and RF sputtering, which offers industry-friendly benefits, including faster deposition at medium energy, cost-effectiveness, and scalability. The surface morphology of the film was characterized using a transmission electron microscope; identification and quantification of the elements were carried out using energy-dispersive x-ray spectroscopy (EDS), which confirmed the Tb–Co–Fe film is Fe-rich with clear Tb and Co incorporation, consistent with Fe2RE-type phases that support strong magnetic behavior. The lattice was scanned using selected area electron diffraction, showing an hcp lattice with lattice spacing of 2.25 ± 0.05 Å; however, Tb–(Co, Fe) at the composition found by EDS is typically amorphous or nanocrystalline, so “lattice spacing” refers to the nearest-neighbor/short-range order distance inferred from the first diffuse ring, not a true crystal lattice parameter. Magnetic properties studied using a vibrating sample magnetometer at several angles between the sample normal and the magnetic field show magnetic anisotropy with an easy axis at 0° and a hard axis at 90°, typical for magnetically doped thin films with a strong twofold anisotropy with an anisotropy ratio of 2.2. This magnetic alloy is promising for potential applications in low-power ultrafast spintronic technologies due to its low symmetry and large spin–orbit coupling.