Measurement of the magneto-optical response of Fe and CrO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>epitaxial films by pump-probe spectroscopy: Evidence for spin-charge separation

Carpene, E.; Boschini, Fabio; Hedayat, Hamoon; Piovera, C.; Dallera, C.; Puppin, E.; Mansurova, M.; Münzenberg, Markus; Zhang, X.; Gupta, Arunava

doi:10.1103/physrevb.87.174437

Cited by 26 publications

(18 citation statements)

References 33 publications

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“…1 and Supplementary Discussion, we discuss aspects consolidating the feasibility of MSHG for investigating Eu 1 À x Gd x O magnetism in a pump/probe experiment. We show that contributions to the MSHG response that are not magnetic in origin but caused by the carrier non-equilibrium distribution after the optical excitation 31,32 are negligible. We also explain why crystallographic, surface and other contributions to the MSHG signal do not interfere with our experiment.…”

Section: Resultsmentioning

confidence: 85%

Ultrafast optical tuning of ferromagnetism via the carrier density

et al. 2015

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Interest in manipulating the magnetic order by ultrashort laser pulses has thrived since it was observed that such pulses can be used to alter the magnetization on a sub-picosecond timescale. Usually this involves demagnetization by laser heating or, in rare cases, a transient increase of magnetization. Here we demonstrate a mechanism that allows the magnetic order of a material to be enhanced or attenuated at will. This is possible in systems simultaneously possessing a low, tunable density of conduction band carriers and a high density of magnetic moments. In such systems, the thermalization time can be set such that adiabatic processes dominate the photoinduced change of the magnetic order-the three-temperature model for interacting thermalized electron, spin and lattice reservoirs is bypassed. In ferromagnetic Eu 1 À x Gd x O, we thereby demonstrate the strengthening as well as the weakening of the magnetic order by B10% and within r3 ps by optically controlling the magnetic exchange interaction.

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Section: Resultsmentioning

confidence: 85%

Ultrafast optical tuning of ferromagnetism via the carrier density

et al. 2015

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“…The evidence for the spin temperature evolution in CrO 2 after the optical pump is provided by the magneto-optical Kerr effect 27,28 (MOKE), which refers to a change in the polarization state of reflected light and is proportional to the material's magnetization. In time-resolved MOKE (TRMOKE), the pump-induced change in magnetization is recorded [29][30][31][32][33][34] . In CrO 2 , a slow demagnetization over hundreds of picoseconds follows the optical pump excitation, as the spin temperature rises due to the spin-lattice coupling 27,28 .…”

Section: Discussion Of the Resultsmentioning

confidence: 99%

Role of spin fluctuations in the conductivity ofCrO2

et al. 2016

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We present a time-resolved terahertz spectroscopic study of the half-metallic ferromagnet CrO 2 .The ultrafast conductivity dynamics excited by an optical pump displays a very short (several picoseconds) and a very long (several hundred picoseconds) characteristic time scales. We attribute the former to the electron-phonon relaxation and the latter to the spin-lattice relaxation. We use this distinction to quantify the relative contribution of the scattering by spin fluctuations to the resistivity of CrO 2 : we find that they contribute less than one half of all scattering events below room temperature. This contribution rises to ∼ 70% as the temperature approaches T C =390 K.The small effect of spin fluctuations on the resistivity is unexpected in the light of the proposed double-exchange nature of the electronic and magnetic properties of CrO 2 .

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“…3 What is this insight alike we get through experiments on ultrafast timescales? Many observations in a large number of experiments over the last years [4][5][6][7][8][9][10][11][12][13][14] reveal us different insights, and since typical electronic excitations are found on femtosecond time scales, fundamental discoveries of the solid state can be made in the femtosecond region. Femtosecond laser experiments can be compared with particle accelerator experiments in nuclear physics aiming to break the ground state into fundamental excitations.…”

Section: Introduction: Current Understanding Of Ultrafast Processesmentioning

confidence: 99%

Perspective: Ultrafast magnetism and THz spintronics

Walowski

Münzenberg

2016

Journal of Applied Physics

335

205

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This year the discovery of femtosecond demagnetization by laser pulses is 20 years old. For the first time, this milestone work by Bigot and coworkers gave insight directly into the time scales of microscopic interactions that connect the spin and electron system. While intense discussions in the field were fueled by the complexity of the processes in the past, it now became evident that it is a puzzle of many different parts. Rather than providing an overview that has been presented in previous reviews on ultrafast processes in ferromagnets, this perspective will show that with our current depth of knowledge the first applications are developed: THz spintronics and all-optical spin manipulation are becoming more and more feasible. The aim of this perspective is to point out where we can connect the different puzzle pieces of understanding gathered over 20 years to develop novel applications. Based on many observations in a large number of experiments. Differences in the theoretical models arise from the localized and delocalized nature of ferromagnetism. Transport effects are intrinsically non-local in spintronic devices and at interfaces. We review the need for multiscale modeling to address the processes starting from electronic excitation of the spin system on the picometer length scale and sub-femtosecond time scale, to spin wave generation, and towards the modeling of ultrafast phase transitions that altogether determine the response time of the ferromagnetic system. Today, our current understanding gives rise to the first usage of ultrafast spin physics for ultrafast magnetism control: THz spintronic devices. This makes the field of ultrafast spin-dynamics an emerging topic open for many researchers right now. Published by AIP Publishing. [http://dx

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Measurement of the magneto-optical response of Fe and CrO2epitaxial films by pump-probe spectroscopy: Evidence for spin-charge separation

Cited by 26 publications

References 33 publications

Ultrafast optical tuning of ferromagnetism via the carrier density

Ultrafast optical tuning of ferromagnetism via the carrier density

Role of spin fluctuations in the conductivity ofCrO2

Perspective: Ultrafast magnetism and THz spintronics

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