Annealing effect on the structure, magnetic characteristic, surface energy and optical property of Co40Fe40W10B10 thin films

Abstract

X-ray diffraction indicated an amorphous state of all annealed films, indicating that boron in CoFeW films could refine grain size and low annealing temperatures did not induce sufficient thermal driving force to support grain growth. The saturation magnetization (Ms) and low-frequency alternate-current magnetic susceptibility (χac) increased with the increase in the thicknesses and annealing temperatures, indicating the thickness effect and magneto-nanocrystalline anisotropy. The highest Ms and χac values of Co40Fe40W10B10 films were estimated to be 1233 emu/cm3 and 2.8, at an annealing temperature of 350 °C and thickness of 100 nm. Surface energy increased with the increase in thickness and annealing temperature. The highest surface energy of 100 nm thick Co40Fe40W10B10 film was 38.52 mJ/mm2 at 350 °C. The Co40Fe40W10B10 film had the highest transmittance when annealing temperature was 200 °C and 10 nm, and its transmittance rate was 32.7%. The transmittance decreased with the increase in thickness and annealing temperatures, while a higher thickness may inhibit the transfer of photon signals through the film, causing a low transmittance. In this study, the optimal condition of magnetic and adhesive properties of Co40Fe40W10B10 film was found to be 100 nm with annealing at 350 °C due to high Ms, large χac, and strong adhesion.