Optimizing high-frequency properties of stripe domain ferrite doped CoFe thin films by means of a Ta buffer layer

• Published in: Journal of physics. D, Applied physics Vol. 46; no. 41; pp. 415001 - 1-7
• Main Authors: Chai, Guozhi, Phuoc, Nguyen N, Ong, C K
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 16.10.2013; Institute of Physics
• Subjects: Buffer layers; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Ferrite doped CoFe thin film; High frequency properties; Magnetic properties and materials; Magnetic properties of monolayers and thin films; Magnetic properties of surface, thin films and multilayers; Physics; Stripe domain; Ta buffer layer; Buffer layer; Nickel base alloys; Stripe domains; Nickel alloys; Doping; Iron alloys; Permeability; Magnetic thin films; Thin films; Ferrites; Permalloy; Resonance frequency; High frequency; Cobalt alloys
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/46/41/415001

The permeability μ and resonant frequency fr of stripe domain ferrite doped CoFe thin films are enhanced from 14 to 22 and 6.0 GHz to 6.4 GHz, respectively, by using Ta buffer layer. The observed enhancement of both permeability and resonant frequency seems to deviate from Snoek's law which expects the value of μ decrease as the fr increases. Compared to the case of using Permalloy (Ni80Fe20) buffer layer where μ is enhanced to 25 and fr is reduced to 4.1 GHz, the present result suggests that the employment of Ta buffer layer may be useful in the quest for high permeability magnetic thin films at GHz frequency range.