title: Shape- and Interface-Induced Control of Spin Dynamics of Two-Dimensional Bicomponent Magnonic Crystals.
abstract: Controlled fabrication of periodically arranged embedded nanostructures with strong interelement interaction through the interface between the two different materials has great potential applications in spintronics, spin logic, and other spin-based communication devices. Here, we report the fabrication of two-dimensional bicomponent magnonic crystals in form of embedded Ni80Fe20 nanostructures in Co50Fe50 thin films by nanolithography. The spin wave (SW) spectra studied by a broadband ferromagnetic resonance spectroscopy showed a significant variation as the shape of the embedded nanostructure changes from circular to square. Significantly, in both shapes, a minimum in frequency is obtained at a negative value of bias field during the field hysteresis confirming the presence of a strong exchange coupling at the interface between the two materials, which can potentially increase the spin wave propagation velocity in such structures leading to faster gigahertz frequency magnetic communication and logic devices. The spin wave frequencies and bandgaps show bias field tunability, which is important for above device applications. Numerical simulations qualitatively reproduced the experimental results, and simulated mode profiles revealed the spatial distribution of the SW modes and internal magnetic fields responsible for this observation. Development of such controlled arrays of embedded nanostructures with improved interface can be easily applied to other forms of artificial crystals.
authors.affiliation: Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences , Block JD, Sector III, Salt Lake, Kolkata 700 106, India.
authors.forename: Samiran
authors.initials: S
authors.lastname: Choudhury
authors.affiliation: Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences , Block JD, Sector III, Salt Lake, Kolkata 700 106, India.
authors.forename: Susmita
authors.initials: S
authors.lastname: Saha
authors.affiliation: Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences , Block JD, Sector III, Salt Lake, Kolkata 700 106, India.
authors.forename: Ruma
authors.initials: R
authors.lastname: Mandal
authors.affiliation: Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences , Block JD, Sector III, Salt Lake, Kolkata 700 106, India.
authors.forename: Saswati
authors.initials: S
authors.lastname: Barman
authors.affiliation: Institute for Solid State Physics, University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan.|RIKEN-CEMS , 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: YoshiChika
authors.initials: Y
authors.lastname: Otani
authors.affiliation: Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences , Block JD, Sector III, Salt Lake, Kolkata 700 106, India.
authors.forename: Anjan
authors.initials: A
authors.lastname: Barman
keywords: ferromagnetic resonance; magnetization dynamics; magnonic crystal; nanofabrication; nanomagnetism; spin waves