title: Universal dependence of the spin wave band structure on the geometrical characteristics of two-dimensional magnonic crystals.
abstract: In the emerging field of magnon-spintronics, spin waves are exploited to encode, carry and process information in materials with periodic modulation of their magnetic properties, named magnonic crystals. These enable the redesign of the spin wave dispersion, thanks to its dependence on the geometric and magnetic parameters, resulting in the appearance of allowed and forbidden band gaps for specific propagation directions. In this work, we analyze the spin waves band structure of two-dimensional magnonic crystals consisting of permalloy square antidot lattices with different geometrical parameters. We show that the frequency of the most intense spin-wave modes, measured by Brillouin light scattering, exhibits a universal dependence on the aspect ratio (thickness over width) of the effective nanowire enclosed between adjacent rows of holes. A similar dependence also applies to both the frequency position and the width of the main band gap of the fundamental (dispersive) mode at the edge of the first Brillouin zone. These experimental findings are successfully explained by calculations based on the plane-wave method. Therefore, a unified vision of the spin-waves characteristics in two-dimensional antidot lattices is provided, paving the way to the design of tailored nanoscale devices, such as tunable magnonic filters and phase-shifters, with predicted functionalities.
authors.affiliation: Istituto Officina dei Materiali del CNR (CNR-IOM), Unità di Perugia, c/o Dipartimento di Fisica e Geologia, Perugia, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Tacchi
authors.affiliation: Faculty of Physics, Adam Mickiewicz University in Poznan, Umultowska 85, Poznan 61-614, Poland.
authors.forename: P
authors.initials: P
authors.lastname: Gruszecki
authors.affiliation: Dipartimento di Fisica e Geologia, Università di Perugia, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Madami
authors.affiliation: Dipartimento di Fisica e Geologia, Università di Perugia, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Carlotti
authors.affiliation: Faculty of Physics, Adam Mickiewicz University in Poznan, Umultowska 85, Poznan 61-614, Poland.
authors.forename: J W
authors.initials: JW
authors.lastname: Kłos
authors.affiliation: Faculty of Physics, Adam Mickiewicz University in Poznan, Umultowska 85, Poznan 61-614, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Krawczyk
authors.affiliation: Information Storage Materials Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore.
authors.forename: A
authors.initials: A
authors.lastname: Adeyeye
authors.affiliation: Istituto Officina dei Materiali del CNR (CNR-IOM), Unità di Perugia, c/o Dipartimento di Fisica e Geologia, Perugia, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Gubbiotti