Combinatorial sputtering synthesis of TbCu₇-type Sm-Fe based compounds: A study on phase, composition, and extrinsic magnetic properties

We investigated the effect of composition on the phase and extrinsic magnetic properties of TbCu₇-type SmFe-based compounds using a combinatorial sputtering technique. Composition-spread thin films of SmFe_x (x=6.4–12.7) and SmFe_xN (x=6.8–12.8) were synthesized using a linear shutter-assisted combinatorial sputtering technique. A high-throughput composition, phase, and magnetic characterization were performed on 18 different locations along the film using X-ray diffraction (XRD), X-ray fluorescence (XRF), and magneto-optical Kerr effect (MOKE) magnetometry. The optimal composition with the highest fraction of the main phase was found to be in SmFe_9.8 and SmFe_9.5N and beyond this composition, the α-Fe secondary ferromagnetic phase emerges. The coercive field and remanence of the SmFe_9.5N are estimated to be ∼0.8 T and ∼1.2 T, respectively. Further, scanning transmission electron microscopy (STEM) was performed at SmFe_9.5N to correlate the microstructure with their extrinsic magnetic properties. Overall, this study demonstrates the impact of composition variation on the phase and extrinsic magnetic properties of TbCu₇-type SmFe-based compounds, which can be utilized to tailor magnetic properties for targeted advanced magnet applications.