This study investigated Co₄₀Fe₄₀W₂₀ single-layer thin films according to their corresponding structure, grain size, contact angle, and surface energy characteristics. Co₄₀Fe₄₀W₂₀ alloy thin films of different thicknesses, ranging from 10 to 50 nm, were sputtered on Si(100) substrates by DC magnetron sputtering. The thin films were annealed under three conditions: as-deposited, 250 °C, and 350 °C temperatures, respectively. The Scherrer equation was applied to calculate the grain size of Co₄₀Fe₄₀W₂₀ thin films. The results show that the grain size of CoFe(110) increased simultaneously with the increase of post-annealing temperature, suggesting that the crystallinity of Co₄₀Fe₄₀W₂₀ thin films increased with the post-annealing temperature. Moreover, the contact angles of all Co₄₀Fe₄₀W₂₀ thin films were all less than 90°, suggesting that Co₄₀Fe₄₀W₂₀ thin films show changes in the direction of higher hydrophilicity. However, we found that their contact angles decreased as the grain size of CoFe increased. Finally, the Young equation was applied to calculate the surface energy of Co₄₀Fe₄₀W₂₀ thin films. After post-annealing, the surface energy of Co₄₀Fe₄₀W₂₀ thin films increased with the rising post-annealing temperature. This is the highest value of surface energy observed for 350 °C. In addition, the surface energy increased as the contact angle of Co₄₀Fe₄₀W₂₀ thin films decreased. The high surface energy means stronger adhesion, allowing the formation of multilayer thin films with magnetic tunneling junctions (MTJs). The sheet resistance of the as-deposited and thinner CoFeW films is larger than annealed and thicker CoFeW films. When the thickness is from 10 nm to 50 nm, the hardness and Young’s modulus of the CoFeW film also show a saturation trend.

The structure, magnetic properties, optical properties and adhesion efficiency of CoFeBY films were studied. Co₄₀Fe₄₀B₁₀Y₁₀ alloy was sputtered onto Si (100) with a thickness of 10–50 nm, and then annealed at room temperature, 100 °C, 200 °C and 300 °C for 1 h. X-ray diffraction (XRD) showed that the CoFeBY films deposited at room temperature are amorphous. Annealing at 100 °C gave the films enough thermal energy to change the structure from amorphous to crystalline. After annealing, the CoFeBY thin film showed a body-centered cubic (BCC) CoFeB (110) characteristic peak at 44°. However, the low-frequency alternative-current magnetic susceptibility (χ_ac) and saturation magnetization (M_S) increased with the increase of thickness. CoFeBY thin films had the highest χ_ac and M_S after annealing at 300 °C compared to that at other temperatures. After annealing at 300 °C, the surface energy of CoFeBY film is the maximum at 50 nm. Higher surface energy indicated stronger adhesion.

Co₆₀Fe₂₀Sm₂₀ thin films were deposited onto glass substrates in a high vacuum setting. The films varied in thickness from 10 to 50 nm and underwent annealing processes at different temperatures: room temperature (RT), 100, 200, and 300 °C. Our analysis encompassed structural, magnetic, electrical, nanomechanical, adhesive, and optical properties in relation to film thickness and annealing temperature. X-ray diffraction (XRD) analysis did not reveal characteristic peaks in Co₆₀Fe₂₀Sm₂₀ thin films due to insufficient growth-driving forces. Electrical measurements indicated reduced resistivity and sheet resistance with increasing film thickness and higher annealing temperatures, owing to hindered current-carrier transport resulting from the amorphous structure. Atomic force microscope (AFM) analysis showed a decrease in surface roughness with increased thickness and annealing temperature. The low-frequency alternating current magnetic susceptibility (χ_ac) values increased with film thickness and annealing temperature. Nanoindentation analysis demonstrated reduced film hardness and Young’s modulus with thicker films. Contact angle measurements suggested a hydrophilic film. Surface energy increased with greater film thickness, particularly in annealed films, indicating a decrease in contact angle contributing to this increase. Transmittance measurements have revealed intensified absorption and reduced transmittance with thicker films. In summary, the surface roughness of CoFeSm films at different annealing temperatures significantly influenced their magnetic, electrical, adhesive, and optical properties. A smoother surface reduced the pinning effect on the domain walls, enhancing the χ_ac value. Additionally, diminished surface roughness led to a lower contact angle and higher surface energy. Additionally, smoother surfaces exhibited higher carrier conductivity, resulting in reduced electrical resistance. The optical transparency decreased due to the smoother surface of Co₆₀Fe₂₀Sm₂₀ films.