title: Optically induced tunable magnetization dynamics in nanoscale co antidot lattices.
abstract: We report the time-domain measurements of optically induced precessional dynamics in a series of Co antidot lattices with fixed antidot diameter of 100 nm and with varying lattice constants (S) between 200 and 500 nm. For the sparsest lattice, we observe two bands of precessional modes with a band gap, which increases substantially with the decrease in S down to 300 nm. At S = 200 nm, four distinct bands with significant band gaps appear. The numerically calculated mode profiles show various localized and extended modes with the propagation direction perpendicular to the bias magnetic field. We numerically demonstrate some composite antidot structures with very rich magnonic spectra spreading between 3 and 27 GHz based upon the above experimental observation.
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 700 098, India.
authors.forename: Ruma
authors.initials: R
authors.lastname: Mandal
authors.forename: Susmita
authors.initials: S
authors.lastname: Saha
authors.forename: Dheeraj
authors.initials: D
authors.lastname: Kumar
authors.forename: Saswati
authors.initials: S
authors.lastname: Barman
authors.forename: Semanti
authors.initials: S
authors.lastname: Pal
authors.forename: Kaustuv
authors.initials: K
authors.lastname: Das
authors.forename: Arup Kumar
authors.initials: AK
authors.lastname: Raychaudhuri
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Fukuma
authors.forename: YoshiChika
authors.initials: Y
authors.lastname: Otani
authors.forename: Anjan
authors.initials: A
authors.lastname: Barman