Laser-Induced Ultrafast Magnetic Phenomena

Carva, Karel; Baláž, Pavel; Radu, Ilie

doi:10.1016/bs.hmm.2017.09.003

Cited by 30 publications

(32 citation statements)

References 402 publications

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“…The hot electrons will also quickly start to transfer energy and angular momentum to other degrees of freedom such as lattice and spin excitations [5]. At about 1-2 ps the dominant part of this energy and spin redistribution in the sample is completed and incoherent transversal spin excitations [55] with a high spin temperature are present on the Fe atoms.…”

Section: Discussionmentioning

confidence: 99%

“…An early time-resolved magneto-optical Kerr effect (trMOKE) study demonstrated an unexpected, ultrafast demagnetization of a ferromagnetic Ni foil within 1ps [4]. Since then, extensive investigations have been conducted to find further novel photo-induced magnetic phenomena and explain their mechanisms [5]. One of the studied phenomena is the distinct, element-specific demagnetization behavior observed in multisublattice materials, as e.g.…”

Section: Introductionmentioning

confidence: 99%

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Ultrafast demagnetization of Pt magnetic moment in L1₀-FePt probed by magnetic circular dichroism at a hard x-ray free electron laser

et al. 2019

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Unraveling the origin of ultrafast demagnetization in multisublattice ferromagnetic materials requires femtosecond x-ray techniques to trace the magnetic moment dynamics on individual elements, but this could not yet be achieved in the hard x-ray regime. We demonstrate here the first ultrafast demagnetization dynamics in the ferromagnetic heavy 5d-transition metal Pt using circularlypolarized hard x-rays at an x-ray free electron laser (XFEL). The decay time of laser-induced demagnetization of L1 0 -FePt is determined to be 0.61 0.04 ps Pt t =  using time-resolved x-ray magnetic circular dichroism at the Pt L 3 edge, whereas magneto-optical Kerr measurements indicate the decay time for the total magnetization as 0.1 ps total t < . A transient magnetic state with a photomodulated ratio of the 3d and 5d magnetic moments is demonstrated for pump-probe delays larger than 1 ps. We explain this distinct photo-modulated transient magnetic state by the induced-moment behavior of the Pt atom and the x-ray probing depth. Our findings pave the way for the future use of XFELs to disentangle atomic spin dynamics contributions.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ultrafast demagnetization of Pt magnetic moment in L1₀-FePt probed by magnetic circular dichroism at a hard x-ray free electron laser

et al. 2019

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“…The DyCo 5 material has also been proposed to be suitable for heat-assisted magnetic recording near room temperature [7]. For the archetypical GdFeCo and other RE-TM ferrimagnets like TbFe, TbCo it has been demonstrated that their magnetization can be controlled using femtosecond laser pulses at large lateral length scales and at the nanoscale, without applying any external magnetic field [8,9,10,11,12]. RE-TM ferrimagnetic alloys can be tuned to behave as true antiferromagnets at a compensation temperature where the magnetic moments of the RE and TM sub-lattices are equal in size but oppositely oriented, leading to a zero net magnetization.…”

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confidence: 99%

X-ray magnetic linear dichroism as a probe for non-collinear magnetic state in ferrimagnetic single layer exchange bias systems

Luo

Ryll

Back

et al. 2019

Sci Rep

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Ferrimagnetic alloys are extensively studied for their unique magnetic properties leading to possible applications in perpendicular magnetic recording, due to their deterministic ultrafast switching and heat assisted magnetic recording capabilities. On a prototype ferrimagnetic alloy we demonstrate fascinating properties that occur close to a critical temperature where the magnetization is vanishing, just as in an antiferromagnet. From the X-ray magnetic circular dichroism measurements, an anomalous ‘wing shape’ hysteresis loop is observed slightly above the compensation temperature. This bears the characteristics of an intrinsic exchange bias effect, referred to as atomic exchange bias. We further exploit the X-ray magnetic linear dichroism (XMLD) contrast for probing non-collinear states which allows us to discriminate between two main reversal mechanisms, namely perpendicular domain wall formation versus spin-flop transition. Ultimately, we analyze the elemental magnetic moments for the surface and the bulk parts, separately, which allows to identify in the phase diagram the temperature window where this effect takes place. Moreover, we suggests that this effect is a general phenomenon in ferrimagnetic thin films which may also contribute to the understanding of the mechanism behind the all optical switching effect.

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“…The aforementioned models use certain assumptions, and take a parameterization approach to fit experiments [ 10 , 42 ]. In contrast, a fully ab initio real-time time-dependent density functional theory (rt-TDDFT) without requiring any empirical parameters is highly desired to describe the ultrafast demagnetization [ 43 , 44 ].…”

Section: Ultrafast Laser-induced Magnetization Dynamicsmentioning

confidence: 99%

Ultrafast optical manipulation of magnetic order in ferromagnetic materials

Wang

Liu

2020

Nano Convergence

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The interaction between ultrafast lasers and magnetic materials is an appealing topic. It not only involves interesting fundamental questions that remain inconclusive and hence need further investigation, but also has the potential to revolutionize data storage technologies because such an opto-magnetic interaction provides an ultrafast and energy-efficient means to control magnetization. Fruitful progress has been made in this area over the past quarter century. In this paper, we review the state-of-the-art experimental and theoretical studies on magnetization dynamics and switching in ferromagnetic materials that are induced by ultrafast lasers. We start by describing the physical mechanisms of ultrafast demagnetization based on different experimental observations and theoretical methods. Both the spin-flip scattering theory and the superdiffusive spin transport model will be discussed in detail. Then, we will discuss laser-induced torques and resultant magnetization dynamics in ferromagnetic materials. Recent developments of all-optical switching (AOS) of ferromagnetic materials towards ultrafast magnetic storage and memory will also be reviewed, followed by the perspectives on the challenges and future directions in this emerging area.

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Laser-Induced Ultrafast Magnetic Phenomena

Cited by 30 publications

References 402 publications

Ultrafast demagnetization of Pt magnetic moment in L1₀-FePt probed by magnetic circular dichroism at a hard x-ray free electron laser

Ultrafast demagnetization of Pt magnetic moment in L1₀-FePt probed by magnetic circular dichroism at a hard x-ray free electron laser

X-ray magnetic linear dichroism as a probe for non-collinear magnetic state in ferrimagnetic single layer exchange bias systems

Ultrafast optical manipulation of magnetic order in ferromagnetic materials

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Laser-Induced Ultrafast Magnetic Phenomena

Cited by 30 publications

References 402 publications

Ultrafast demagnetization of Pt magnetic moment in L10-FePt probed by magnetic circular dichroism at a hard x-ray free electron laser

Ultrafast demagnetization of Pt magnetic moment in L10-FePt probed by magnetic circular dichroism at a hard x-ray free electron laser

X-ray magnetic linear dichroism as a probe for non-collinear magnetic state in ferrimagnetic single layer exchange bias systems

Ultrafast optical manipulation of magnetic order in ferromagnetic materials

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Ultrafast demagnetization of Pt magnetic moment in L1₀-FePt probed by magnetic circular dichroism at a hard x-ray free electron laser

Ultrafast demagnetization of Pt magnetic moment in L1₀-FePt probed by magnetic circular dichroism at a hard x-ray free electron laser