Domain Dynamics in Thin Solid Films Following Ultrashort Pulse Excitation

Dean, Jesse; Rench, D. W.; Samarth, N.; Driel, H. M. van

doi:10.1103/physrevlett.111.035701

Cited by 5 publications

(13 citation statements)

References 37 publications

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“…A model in which the microstructure dynamics of the MnAs layer is determined by the step sequence suggested above seems to frame all our experimental findings except one, i.e., the apparent intensity regain of the 2nd order Bragg peak after~200 ps (see Figures 4c and 6a,c). The oscillatory behavior of the scattered intensity reported by Dean et al [19] may provide an explanation for this intensity regain, since, if one assumes that the intensity modulations are due to oscillations of the fractional α/β components, the 2nd order peak would vary with twice the frequency of the 1st order one. Our temperature and fluence dependent analysis, though, shows that the laser pulse favours the formation of a laterally homogeneous MnAs layer over the reorganization of the α and β fractions within the stripes.…”

Section: Electron-spin-phonon Coupling α→β Transition and Time Evolumentioning

confidence: 88%

“…This description of the MnAs microstructure evolution implies that we will never observe an increase of the stripe-related Bragg peak intensity. This situation should be encountered at low temperatures (T < 25 • C) if one assumes that the deposited energy modulates the width of α and β stripes in a quasi-static T-driven α→β transition [19]. Since over the interaction volume the laser pulse leads to a complete single-phase MnAs transformation, driven by the local energy release to the lattice, the stripes with a long-range order can be destroyed, but their formation or growth at sub-ns timescales is never favored.…”

Section: Electron-spin-phonon Coupling α→β Transition and Time Evolumentioning

confidence: 99%

“…This study made use of non-resonant 130 nm radiation and could span a limited time range of~100 ps. A laser-based scattering experiment [19] investigated longer timescales, up to microseconds, showing an overall decrease of the diffracted intensity up to 400 ps, followed by a damped oscillatory behavior up to several ns. The results reported in these articles are at least partly in contrast over the common time range, showing either a fast decrease [18] or an increase [19] of the first order of Bragg peak intensity within the first 15 ps after the laser pulse.…”

Section: Introductionmentioning

confidence: 99%

“…A laser-based scattering experiment [19] investigated longer timescales, up to microseconds, showing an overall decrease of the diffracted intensity up to 400 ps, followed by a damped oscillatory behavior up to several ns. The results reported in these articles are at least partly in contrast over the common time range, showing either a fast decrease [18] or an increase [19] of the first order of Bragg peak intensity within the first 15 ps after the laser pulse. Following our previous time-resolved diffraction experiment on Fe/MnAs/GaAs(001) carried out at the x-ray-ulraviolet (XUV) free-electron laser (FEL) source FERMI [14], the main goal of this study is to get more input for correlating the magnetic response of the Fe overlayer with the temporal evolution of the MnAs microstructure.…”

Section: Introductionmentioning

confidence: 99%

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Dynamics of the MnAs α/β-Striped Microstructure and of the Fe Magnetization Reversal in Fe/MnAs/GaAs(001): An Optical-Laser Pump–Free-Electron-Laser Probe Scattering Experiment

et al. 2017

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It was shown recently that the Fe magnetization reversal in the Fe/MnAs/GaAs(001) epitaxial system, attained by temperature control of the regular stripe pattern of the MnAs α-and β-phases, can also be driven by an ultrashort optical laser pulse. In the present time-resolved scattering experiment, we address the dynamics of the MnAs α-β self-organized stripe pattern induced by a 100 fs optical laser pulse, using as a probe the XUV radiation from the FERMI free-electron laser. We observe a loss in the diffraction intensity from the ordered α-β stripes that occurs at two characteristic timescales in the range of~10 −12 and~10 −10 s. We associate the first intensity drop with ultrafast electron-lattice energy exchange processes within the laser-MnAs interaction volume and the second with thermal diffusion towards the MnAs/GaAs interface. With the support of model calculations, the observed dynamics are interpreted in terms of the

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Section: Electron-spin-phonon Coupling α→β Transition and Time Evolumentioning

confidence: 88%

Section: Electron-spin-phonon Coupling α→β Transition and Time Evolumentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dynamics of the MnAs α/β-Striped Microstructure and of the Fe Magnetization Reversal in Fe/MnAs/GaAs(001): An Optical-Laser Pump–Free-Electron-Laser Probe Scattering Experiment

et al. 2017

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“…Regrowth of the periodic domains can take up to microseconds, depending on the initial temperature of the film. Hence we observe the dynamics over 7 orders of magnitude in time [1]. Specular second harmonic generation provides complementary information by monitoring the spatially averaged value of the surface strain field.…”

mentioning

confidence: 98%

Ultrafast dynamics of ferromagnetic/paramagnetic nanowires in MnAs thin films

Dean

Driel

2014

2014 16th International Conference on Transparent Optical Networks (ICTON)

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Thin films of MnAs on GaAs(001) possess a coexisting phase of ferromagnetic and paramagnetic periodic nanostripes between approximately 10 and 40 °C. The periodic stripes reflect an interplay between misfit and elastic strain. The films offer the possibility of using ultrafast laser heating to switch the magnetic properties for possible applications in information technology. Employing 1 kHz, 775 nm, 150 fs pump pulses and timeresolved optical diffraction and second harmonic generation we have time-resolved the dynamics of the magnetic nanowires in 150 and 190 nm thickness films to observe their destruction and regrowth. We find that the strong periodic elastic strain responsible for the periodic magnetic/structural stripes strongly influences the erasure dynamics while heat diffusion in the substrate governs stripe regrowth.From the time resolved diffraction of a 400 nm probe pulse we observe that erasure of the stripes occurs on a 5 ns time scale with the evolving periodic strain field leading to oscillation of the domains at shorter times. Regrowth of the periodic domains can take up to microseconds, depending on the initial temperature of the film. Hence we observe the dynamics over 7 orders of magnitude in time [1]. Specular second harmonic generation provides complementary information by monitoring the spatially averaged value of the surface strain field. In the periodic phase the strain field collapses in about 100 ps following the pump pulse, too long a time to explain using equilibrium thermodynamics concepts, and likely related to non-equilibrium latent heat dynamics. The surface strain recovers on a 1 ns time scale [2].Our work reveals that strain-induced magnetic domains in thin films cannot be erased in less than 100's of ps and that the recovery of the domains, determined by heat diffusion, takes several microseconds. This imposes limitations on the applications of optical switching of magnetic domains for information technology applications. REFERENCES[1] J.J. Dean, D.W. Rench, N. Samarth, and H.M. van Driel: Domain dynamics in thin solid films following ultrashort pulse excitation, Phys. Rev. Lett. 111, 035701 (2013). [2] J.J. Dean, C. Lange, and H.M. van Driel: Ultrafast surface strain dynamics in MnAs thin films observed with second harmonic generation, Phys. Rev. B 89, 024102 (2014).

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Thermally induced magnetization switching in Fe/MnAs/GaAs(001): selectable magnetic configurations by temperature and field control

Spezzani

Vidal

Delaunay

et al. 2015

Sci Rep

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Spintronic devices currently rely on magnetization control by external magnetic fields or spin-polarized currents. Developing temperature-driven magnetization control has potential for achieving enhanced device functionalities. Recently, there has been much interest in thermally induced magnetisation switching (TIMS), where the temperature control of intrinsic material properties drives a deterministic switching without applying external fields. TIMS, mainly investigated in rare-earth–transition-metal ferrimagnets, has also been observed in epitaxial Fe/MnAs/GaAs(001), where it stems from a completely different physical mechanism. In Fe/MnAs temperature actually modifies the surface dipolar fields associated with the MnAs magnetic microstructure. This in turn determines the effective magnetic field acting on the Fe overlayer. In this way one can reverse the Fe magnetization direction by performing thermal cycles at ambient temperatures. Here we use element selective magnetization measurements to demonstrate that various magnetic configurations of the Fe/MnAs/GaAs(001) system are stabilized predictably by acting on the thermal cycle parameters and on the presence of a bias field. We show in particular that the maximum temperature reached during the cycle affects the final magnetic configuration. Our findings show that applications are possible for fast magnetization switching, where local temperature changes are induced by laser excitations.

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Domain Dynamics in Thin Solid Films Following Ultrashort Pulse Excitation

Cited by 5 publications

References 37 publications

Dynamics of the MnAs α/β-Striped Microstructure and of the Fe Magnetization Reversal in Fe/MnAs/GaAs(001): An Optical-Laser Pump–Free-Electron-Laser Probe Scattering Experiment

Dynamics of the MnAs α/β-Striped Microstructure and of the Fe Magnetization Reversal in Fe/MnAs/GaAs(001): An Optical-Laser Pump–Free-Electron-Laser Probe Scattering Experiment

Ultrafast dynamics of ferromagnetic/paramagnetic nanowires in MnAs thin films

Thermally induced magnetization switching in Fe/MnAs/GaAs(001): selectable magnetic configurations by temperature and field control

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