Surface Roughness-Induced Changes in Important Physical Features of CoFeSm Thin Films on Glass Substrates during Annealing

Chi-Lon Fern; Wen-Jen Liu; Yung-Huang Chang; Chia-Chin Chiang; Yuan-Tsung Chen; Pei-Xin Lu; Xuan-Ming Su; Shih-Hung Lin; Ko-Wei Lin

doi:10.3390/ma16216989

Surface Roughness-Induced Changes in Important Physical Features of CoFeSm Thin Films on Glass Substrates during Annealing

Materials (Basel). 2023 Oct 31;16(21):6989. doi: 10.3390/ma16216989.

Authors

Chi-Lon Fern¹, Wen-Jen Liu², Yung-Huang Chang³, Chia-Chin Chiang⁴, Yuan-Tsung Chen⁵, Pei-Xin Lu⁵, Xuan-Ming Su⁵, Shih-Hung Lin⁶, Ko-Wei Lin¹

Affiliations

¹ Department of Materials Science and Engineering, National Chung Hsing University, Taichung 40227, Taiwan.
² Department of Materials Science and Engineering, I-Shou University, Kaohsiung 84001, Taiwan.
³ Bachelor Program in Industrial Technology, National Yunlin University of Science and Technology, 123 University Road, Section 3, Yunlin, Douliou 64002, Taiwan.
⁴ Department of Mechanical Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 80778, Taiwan.
⁵ Graduate School of Materials Science, National Yunlin University of Science and Technology, 123 University Road, Section 3, Yunlin, Douliou 64002, Taiwan.
⁶ Department of Electronic Engineering, National Yunlin University of Science and Technology, 123 University Road, Section 3, Yunlin, Douliou 64002, Taiwan.

Abstract

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.

Keywords: adhesion; annealed Co60Fe20Sm20 thin films; low-frequency alternating current magnetic susceptibility (χac); nanoindentation; optimal resonance frequency (fres); surface energy; transmittance.

Abstract

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