Microstructure, mechanical and physical properties of FeCoNiAlMnW high-entropy films deposited by magnetron sputtering

Ferromagnetic Fe33Co30Ni16Al7Mn9W5 high-entropy films of BCC-structure solid solution were synthesized by RF magnetron sputtering with mosaic targets at different substrate temperature of 20 degrees C, 200 degrees C, 400 degrees C and 600 degrees C. Hardness and resistivity were measured by the methods of nanoindentation and four-point probe, respectively. Magnetization hysteresis loops were obtained by a vibrating sample magnetometer. Oriented grain growth of (2 1 1) was observed in the films deposited at 400 degrees C and 600 degrees C. Substrate-temperature elevation led to the variation of film-growth mode. The films showed high hardness and electrical resistivity. Electron-surface scatter generated by mesoscopic-scale roughness played a decisive role in the monotone increase of the films' resistivity as substrate temperature rose. The optimal balance of magnetic and electrical properties was achieved at substrate temperature of 400 degrees C.