Elastic and magnetic dynamics of nanomagnet-ordered arrays impulsively excited by subpicosecond laser pulses.
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.
Comin
A
A
Sincrotrone Trieste, I-34012 Basovizza, Trieste, Italy.
Giannetti
C
C
Samoggia
G
G
Vavassori
P
P
Grando
D
D
Colombi
P
P
Bontempi
E
E
Depero
L E
LE
Metlushko
V
V
Ilic
B
B
Parmigiani
F
F