Damping of Standing Spin Waves in Bismuth-Substituted Yttrium Iron Garnet as Seen via the Time-Resolved Magneto-Optical Kerr Effect

Abstract

We investigate spin-wave resonance modes and their damping in insulating thin films of bismuthsubstituted yttrium iron garnet by performing femtosecond magneto-optical pump-probe experiments. For large magnetic fields in the range below the magnetization saturation, we find that the damping of high-order standing spin-wave (SSW) modes is about 40 times lower than that for the fundamental one. The observed phenomenon can be explained by considering different features of magnetic anisotropy and exchange fields that, respectively, define the precession frequency for fundamental and high-order SSWs. These results provide further insight into SSWs in iron garnets and may be exploited in many new photomagnonic devices.

Generation of spin waves via spin-phonon interaction in a buried dielectric thin film

“…The frequencies of the low-frequency modes are in the range of SW frequencies in Bi-YIG films [43,44,57,58]. To clarify the nature of these modes, we investigated their frequencies as a function of the mode number.…”

“…On the other hand, for around 15 years, the excitation of SSWs with femtosecond laser pulses has been limited to conducting [9,41,42] and semiconducting [13,15,16] magnets. In our recent papers, we demonstrated that a femtosecond laser pulse can excite SSWs in insulating magnetic films of bismuth-substituted YIG with high in-plane magnetic anisotropy [43,44]. In this context, an important fundamental study is to investigate the possibility to take advantage of femtosecond laser pulses to trigger high-frequency SSWs in bismuth-substituted YIG films buried below a thick metallic structure.…”

Noncollinear antiferromagnetic textures driven high harmonic generation from magnetic dynamics in the absence of spin-orbit coupling

“…Interestingly, the use of spin pumping as a driving force instead of optical excitations opens up tantalizing routes toward engineering ultrafast spintronic devices with the grand advantage of being highly scalable. This is in contrast to opto-magnetic studies [8][9][10][11][12][13], where a laser beam is used to excite ultrafast carrier or magnetic dynamics. For instance, in the recent proposal by Kampfrath et at [9], a femtosecond laser beam is used to generate nonequilibrium electron distributions in a geometry constituted of a thin ferromagnetic iron film combined with a thin noble metal layer.…”

Ultrafast control of lattice strain via magnetic circular dichroism

“…From a practical point of view, light polarization (helicity) can thus be used to control any ultrafast phenomena that are influenced by the lattice strain (or lattice heating). For example, in Bi-substituted iron garnets, it was recently demonstrated that an ultrafast heating of lattice can excite high frequency spin waves [20,66,67] and induce a full magnetization switching [68]. By choosing the appropriate pump wavelength to maximize the effect of MCD on lattice heating, it will be therefore possible to use the polarization of light in order to: (i) control the amplitude of the spin waves and (ii) obtain a helicity-dependent optical magnetization switching in magnetic insulators.…”