Structure and temperature effects in electrical conductivity of Fe x Ni1− x and Fe x Со1− x thin-film alloys

Thin-film alloys FexNi1−x and FeхСо1−х (0.2 ≤ х ≤ 0.8) were prepared by electron-beam evaporation in a vacuum. The thickness of the samples varied from 20 to 60 nm. The resistivity of as-deposited FexNi1−x and FeхСо1−х thin-film alloys at room temperature takes values within the range from 20 × 10−7 to 70 × 10−7 Ω m, depending on the concentration of components and thickness. The resistivity of annealed at a temperature of 700 K FexNi1−x and FeхСо1−х thin-film alloys is within the range of 3 × 10−7–20 × 10−7 Ω m. The electron transport properties were found to agree with their crystal structure, which strongly depended on the composition of the alloys. The concentration dependences of resistivity and temperature coefficient of resistance have monotonous characteristics for all samples after heat treatment at 700 K. The temperature coefficient of resistance reaches its minimum value at the maximum Fe content (x = 0.8). It has been found that the temperature dependence of resistivity of thin-film alloys exhibits three characteristic regions due to the low-temperature electron–phonon interaction (T1 = 125 K–Θ1), the electron–magnon interaction (T2 = Θ1–Θ2), and the electron–phonon interaction at high temperatures (T3 = Θ2–700 K).