Synthesis of magneto-dielectric coatings in electron-beam produced plasma in medium vacuum

• Published in: Ceramics international Vol. 47; no. 24; pp. 34704 - 34711
• Main Authors: Zolotukhin, D.B., Tyunkov, A.V., Yushkov, Yu.G., Zhuravlev, V.A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.12.2021
• Subjects: Beam-produced plasma; Electron-beam evaporation; Fore-vacuum plasma-cathode electron source; Magneto-dielectric coatings; Medium vacuum; Multi-layer coatings; Multi-layer coatings; Fore-vacuum plasma-cathode electron source; Medium vacuum; Magneto-dielectric coatings; Electron-beam evaporation; Beam-produced plasma
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2021.09.009

Using sequential electron-beam evaporation of high-temperature dielectric (alumina ceramic) and magnetic (iron) targets in various gas atmospheres (helium, air, and oxygen) in medium vacuum (5–8 Pa), magneto-dielectric coatings with thickness of around 2 μm were deposited from a multicomponent beam plasma at a deposition rate of 0.2–0.3 μm/min. The coating magnetic properties were explored by the ferromagnetic resonance technique, revealing that their effective magnetization depends on the type of operating gas and varied from 4.2 to 6.8 kGs (for deposition in helium) to 0.3 kGs (in oxygen), which is characteristic of oxide ferromagnetic materials and is considerably lower than the corresponding value (∼22 kGs) for thin iron films formed by vacuum arc deposition in high vacuum. X-ray structural analysis of coatings deposited in medium vacuum in helium showed that the magnetic layer has a magnetite (Fe3O4) structure. The alumina ceramic layer provides the dielectric properties of the magneto-dielectric coating; a relative dielectric constant of 6.0 and a conductivity of 8.4 mS/m were achieved.