The structure and surface energy of Ni80Fe20 thin films

Abstract

In this study, NiFe thin films were deposited on a glass substrate at room temperature (RT) or postannealed at 150 and 250°C for 1h; the Ni80Fe20 films were 300–1500Å thick. The structure, surface energy, and average contact angle properties of the NiFe thin films were investigated. X-ray diffraction (XRD) results demonstrated that the NiFe thin films exhibited a face-centred cubic (FCC) structural state. The XRD results also revealed that the NiFe films were more crystalline after post-annealing treatment than they were after RT treatment alone, suggesting that the NiFe crystalline structure exhibited FCC (111) texturing. The NiFe films formed a contact angle of <90° with the test liquids water and diiodomethane, which indicated that the NiFe films were hydrophilic. The surface energy of the NiFe thin films decreased when post-annealing treatment was used and their thickness was increased from 60.4 to 47.9mJ/mm2, suggesting that the surface energy was associated with the crystallinity of the thin films. Therefore, these NiFe thin films exhibit low surface-energy characteristics that can produce a self-cleaning effect.