title: Elastic and magnetic dynamics of nanomagnet-ordered arrays impulsively excited by subpicosecond laser pulses.
abstract: This Letter reports on the first observation of elastic and magnetic dynamics of ordered arrays of permalloy nanodots excited by low-intensity 120 fs light pulses. The first order of the diffraction pattern, generated by the probe beam in a pump-probe configuration, is used for time-resolved reflectivity and time-resolved magneto-optical Kerr effect measurements. The nonadiabatical absorption of the pump triggers an acoustic standing wave, detected by the reflected probe signal, with a frequency related to the array wave vector. Instead, the magneto-optical signal exhibits, on the nanosecond time scale, the signature of the heat-exchange diffusion processes. In addition, a clear oscillation of the magnetic signal, at a frequency close to the frequency of the acoustic wave, is unambiguously detected. Finally, the interplay between the elastic and magnetic dynamics is analyzed and interpreted.
authors.affiliation: Sincrotrone Trieste, I-34012 Basovizza, Trieste, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Comin
authors.forename: C
authors.initials: C
authors.lastname: Giannetti
authors.forename: G
authors.initials: G
authors.lastname: Samoggia
authors.forename: P
authors.initials: P
authors.lastname: Vavassori
authors.forename: D
authors.initials: D
authors.lastname: Grando
authors.forename: P
authors.initials: P
authors.lastname: Colombi
authors.forename: E
authors.initials: E
authors.lastname: Bontempi
authors.forename: L E
authors.initials: LE
authors.lastname: Depero
authors.forename: V
authors.initials: V
authors.lastname: Metlushko
authors.forename: B
authors.initials: B
authors.lastname: Ilic
authors.forename: F
authors.initials: F
authors.lastname: Parmigiani