Coherent Magnetization Precession in Ferromagnetic (Ga,Mn)As Induced by Picosecond Acoustic Pulses

Scherbakov, A. V.; Salasyuk, A. S.; Akimov, A. V.; Liu, X.; Bombeck, M.; Brüggemann, Christian; Yakovlev, D. R.; Sapega, V. F.; Furdyna, J. K.; Bayer, М.

doi:10.1103/physrevlett.105.117204

Cited by 196 publications

(193 citation statements)

References 35 publications

(41 reference statements)

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“…5(a). Here the main feature is the oscillation of the Kerr signal caused by the oscillatory component of magnetization M Z due to the collective precession of the magnetization around its inplane equilibrium orientation at a frequency of ∼4.2 GHz (see inset), as discussed in the literature [22][23][24][25][26][27][28] . The observed precession frequency in the low field limit is well described analytically by the formula,…”

Section: B Long-time Dynamics: Coherent Mn Spin Precessionmentioning

confidence: 72%

“…This includes femtosecond Mn spin canting induced by spin-orbit torques 14,15 via photoexcited non-thermal "transverse" hole spins involving the interplay between spin-orbit and magnetic exchange interaction 16,17 ; femtosecond demagnetization (i.e. decrease of Mn spin amplitude) via dynamical polarization of "longitudinal" holes spins [18][19][20] ; picosecond photoinduced ferromagnetism 21 ; and magnetization precession [22][23][24][25][26][27][28] .…”

Section: Introductionmentioning

confidence: 99%

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Ultrafast probes of nonequilibrium hole spin relaxation in the ferromagnetic semiconductor GaMnAs

Patz

Liu

et al. 2015

Phys. Rev. B

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We report direct measurements of hole spin lifetimes in ferromagnetic GaMnAs carried out by time-and polarization-resolved spectroscopy. Below the Curie temperature, ultrafast photoexcitation of GaMnAs with linearly-polarized light is shown to create a non-equilibrium hole spin population via dynamical polarization of the holes through p-d exchange scattering with ferromagneticallyordered Mn spins. The system is then observed to relax in a distinct three-step recovery process: (i) a femtosecond hole-spin relaxation, on the scale of 160-200 fs, (ii) a picosecond hole-energy relaxation, on the scale of 1-2 ps, and (iii) a coherent, damped Mn spin precession with a period of 250 ps. The transient amplitude of the hole-spin relaxation component diminishes with increasing temperature, directly following the ferromagnetic order of GaMnAs, while the hole-energy amplitude shows negligible temperature change. Our results serve to establish the hole spin lifetimes in the ferromagnetic semiconductor GaMnAs, at the same time demonstrating a novel spectroscopic method for studying non-equilibrium hole spins in the presence of magnetic order and spin exchange interaction.

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Section: B Long-time Dynamics: Coherent Mn Spin Precessionmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Ultrafast probes of nonequilibrium hole spin relaxation in the ferromagnetic semiconductor GaMnAs

Patz

Liu

et al. 2015

Phys. Rev. B

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“…During the growth, when atoms are mobile on the surface, nearest-neighbor Mn pairs on the GaAs (001) surface have a lower energy for the [1][2][3][4][5][6][7][8][9][10] direction compared to the [110] 39 .…”

Section: Annex a Magnetic Anisotropy Coefficientsmentioning

confidence: 99%

Irreversible magnetization switching using surface acoustic waves

et al. 2013

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An analytical and numerical approach is developped to pinpoint the optimal experimental conditions to irreversibly switch magnetization using surface acoustic waves (SAWs). The layers are magnetized perpendicular to the plane and two switching mechanisms are considered. In precessional switching, a small in-plane field initially tilts the magnetization and the passage of the SAW modifies the magnetic anisotropy parameters through inverse magneto-striction, which triggers precession, and eventually reversal. Using the micromagnetic parameters of a fully characterized layer of the magnetic semiconductor (Ga,Mn)(As,P), we then show that there is a large window of accessible experimental conditions (SAW amplitude/wave-vector, field amplitude/orientation) allowing irreversible switching. As this is a resonant process, the influence of the detuning of the SAW frequency to the magnetic system's eigenfrequency is also explored. Finally, another -non-resonantswitching mechanism is briefly contemplated, and found to be applicable to (Ga,Mn)(As,P): SAWassisted domain nucleation. In this case, a small perpendicular field is applied opposite the initial magnetization and the passage of the SAW lowers the domain nucleation barrier.

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“…3 The interplay between magnetization and strain, arising from the spin-orbit interaction, 4 is governed by the magnitude of the magnetostrictive coefficient. 5 In a recent experiment, 6 short light pulses excite picosecond acoustic waves, resulting in fast magnetization changes in a thin film of ͑Ga,Mn͒As. 6 Here we exploit the sensitivity of the magnetization direction to strain to study an efficient, low-power, and low cost method for fast magnetic switching using a strain coupled device that rotates the magnetization between the hard and easy axes at the resonant frequency ͑91 MHz͒ of a surface acoustic wave ͑SAW͒ transducer 7 providing directional, time dependent strain to a micron scale array of Co bars.…”

mentioning

confidence: 99%

“…5 In a recent experiment, 6 short light pulses excite picosecond acoustic waves, resulting in fast magnetization changes in a thin film of ͑Ga,Mn͒As. 6 Here we exploit the sensitivity of the magnetization direction to strain to study an efficient, low-power, and low cost method for fast magnetic switching using a strain coupled device that rotates the magnetization between the hard and easy axes at the resonant frequency ͑91 MHz͒ of a surface acoustic wave ͑SAW͒ transducer 7 providing directional, time dependent strain to a micron scale array of Co bars. Previous experiments have shown changes in the SAW propagation through continuous magnetic thin films of Ni and permalloy with magnetization direction.…”

mentioning

confidence: 99%

Magnetization dynamics triggered by surface acoustic waves

Davis

Baruth

Adenwalla

2010

Applied Physics Letters

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Investigations into fast magnetization switching are of both fundamental and technological interest. Here we present a low-power, remote method for strain driven magnetization switching. A surface acoustic wave propagates across an array of ferromagnetic elements, and the resultant strain switches the magnetization from the easy axis into the hard axis direction. Investigations as a function of applied magnetic field as well as unidirectional anisotropy (the exchange bias) reveal excellent agreement with prediction, confirming the viability of this method.

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Coherent Magnetization Precession in Ferromagnetic (Ga,Mn)As Induced by Picosecond Acoustic Pulses

Cited by 196 publications

References 35 publications

Ultrafast probes of nonequilibrium hole spin relaxation in the ferromagnetic semiconductor GaMnAs

Ultrafast probes of nonequilibrium hole spin relaxation in the ferromagnetic semiconductor GaMnAs

Irreversible magnetization switching using surface acoustic waves

Magnetization dynamics triggered by surface acoustic waves

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