Direct observation of field and temperature induced domain replication in dipolar coupled perpendicular anisotropy films

Hauet, Thomas; Günther, C. M.; Pfau, Bastian; Schabes, M.E.; Thiele, Jan-Ulrich; Rick, R.; Fischer, Peter; Eisebitt, Stefan; Hellwig, Olav

doi:10.1103/physrevb.77.184421

Cited by 44 publications

(28 citation statements)

References 14 publications

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“…Domains present in magnetic thin films with perpendicular anisotropy fall into this category and have been studied in many static and dynamic XMCD-based experiments in the past [19][20][21][22][23][24]. In fact, this class of samples constitutes a widely used model system due to (i) the tunability of their material properties via the multilayer composition; (ii) the possibility to modify the magnetic domain pattern via the magnetic history, e.g., preparing a disordered labyrinth or ordered stripe domain phase, (iii) the flexibility to introduce different magnetic elements and magnetic coupling schemes [25,26]. A further advantage offered by such films is the strong magnetic contrast accessible in scattering experiments due to the pronounced XMCD effect of the absorption resonance of these elements in the soft X-ray photon energy range [27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Irreversible transformation of ferromagnetic ordered stripe domains in single-shot infrared-pump/resonant-x-ray-scattering-probe experiments

et al. 2015

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The evolution of a magnetic domain structure upon excitation by an intense, femtosecond Infra-Red (IR) laser pulse has been investigated using single-shot based time-resolved resonant X-ray scattering at the X-ray Free Electron laser LCLS. A well-ordered stripe domain pattern as present in a thin CoPd alloy film has been used as prototype magnetic domain structure for this study. The fluence of the IR laser pump pulse was sufficient to lead to an almost complete quenching of the magnetization within the ultrafast demagnetization process taking place within the first few hundreds of femtoseconds following the IR laser pump pulse excitation. On longer time scales this excitation gave rise to subsequent irreversible transformations of the magnetic domain structure. Under our specific experimental conditions, it took about 2 nanoseconds before the magnetization started to recover. After about 5 nanoseconds the previously ordered stripe domain structure had evolved into a disordered labyrinth domain structure. Surprisingly, we observe after about 7 nanoseconds the occurrence of a partially ordered stripe domain structure reoriented into a novel direction. It is this domain structure in which the sample's magnetization stabilizes as revealed by scattering patterns recorded long after the initial pump-probe cycle. Using micro-magnetic simulations we can explain this observation based on changes of the magnetic anisotropy going along with heat dissipation in the film.

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Section: Introductionmentioning

confidence: 99%

Irreversible transformation of ferromagnetic ordered stripe domains in single-shot infrared-pump/resonant-x-ray-scattering-probe experiments

et al. 2015

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“…8 and 9) as nonmagnetic layers, and Co (Refs. [5][6][7][8]10) and CoNi (Ref. 8) as magnetic layers, with relatively large (5-60 nm) effective magnetic thicknesses for both remanence [5][6][7][8]10 and fielddependent 6,9,10 measurements.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the technique can image deeply buried magnetic systems and, as a pure photon-based technique (photon-in/ photon-out), can be used in applied magnetic fields. Up to now, soft x-ray holography has focused on [nonmagnetic/ magnetic] n multilayers with perpendicular magnetic anisotropy, [5][6][7][8][9][10] using Pt (Refs. [5][6][7]10) and Pd (Refs.…”

Section: Introductionmentioning

confidence: 99%

Exploring the limits of soft x-ray magnetic holography: Imaging magnetization reversal of buried interfaces (invited)

Camarero¹,

Jiménez²,

Vogel³

et al. 2011

Journal of Applied Physics

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Only a very few experimental techniques can address the microscopic magnetization reversal behavior of the different magnetic layers in a multilayered system with element selectivity. We present an element-selective study of ferromagnetic (FM) [Co/Pt] n multilayers with perpendicular anisotropy exchange-coupled to antiferromagnetic (AFM) FeMn and IrMn films performed with a new experimental set-up developed for both soft x-ray spectroscopy and holography imaging purposes. The spectroscopy analysis allows the quantification of the unpinned (pinned) uncompensated AFM moments, providing direct evidence of its parallel (antiparallel) alignment with respect to the FM moments. The holography experiments give a direct view of both FM and uncompensated AFM magnetic structures, showing that they replicate to each other during magnetization reversal. Remarkably, we show magnetic images for effective thicknesses as small as one monolayer. Our results provide new microscopic insights into the exchange coupling phenomena and explore the sensitivity limits of these techniques. Future trends are also discussed.

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“…We start with pioneering experiments at FLASH demonstrating the feasibility of magnetic scattering at FELs [1,2], then present pump-probe scattering experiments [3,4] as well as the first FEL magnetic imaging experiments [5], and finally discuss a limitation of the scattering methods due to a quenching of the magnetic scattering signal by high-fluence FEL pulses [6]. All of the presented experiments exploit the x-ray magnetic circular dichroism effect [7,8] to obtain element-specific magnetic scattering contrast, as known from synchrotron experiments [9][10][11][12].One of the key problems in modern magnetism research, ultrafast demagnetization discovered by Beaurepaire in 1996 [13], acts on time scales of a few 100 fs, which are not accessible at standard synchrotron radiation sources. Since its discovery, ultrafast demagnetization was studied using optical femtosecond lasers, for a review see e. g.…”

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confidence: 99%

Ultrafast Dynamics of Magnetic Domain Structures Probed by Coherent Free-Electron Laser Light

Müller

Schleitzer

Gutt

et al. 2013

Synchrotron Radiation News

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2 INTRODUCTIONThe free-electron laser (FEL) sources FLASH in Hamburg, LCLS at Stanford and FERMI in Trieste provide XUV to soft x-ray radiation (FLASH and FERMI) or soft to hard x-ray radiation (LCLS) with unprecedented parameters in terms of ultrashort pulse length, high photon flux, and coherence. These properties make FELs ideal tools for studying ultrafast dynamics in matter on a previously unaccessible level. This paper reviews first results obtained at FEL sources during the last years in the field of magnetism research. We start with pioneering experiments at FLASH demonstrating the feasibility of magnetic scattering at FELs [1,2], then present pump-probe scattering experiments [3,4] as well as the first FEL magnetic imaging experiments [5], and finally discuss a limitation of the scattering methods due to a quenching of the magnetic scattering signal by high-fluence FEL pulses [6]. All of the presented experiments exploit the x-ray magnetic circular dichroism effect [7,8] to obtain element-specific magnetic scattering contrast, as known from synchrotron experiments [9][10][11][12].One of the key problems in modern magnetism research, ultrafast demagnetization discovered by Beaurepaire in 1996 [13], acts on time scales of a few 100 fs, which are not accessible at standard synchrotron radiation sources. Since its discovery, ultrafast demagnetization was studied using optical femtosecond lasers, for a review see e. g.[14], and femtoslicing sources [15] at storage ring sources [16,17]. In both cases, spatial resolution is limited due to wavelength or flux limitations. In contrast, FELs combine high time resolution, element selectivity, and the spatial resolving power of xrays with high photon flux and excellent coherence properties. FEL sources, therefore, promise a pivotal step forward in the investigation of ultrafast phenomena on nanometer length scales. The rapid development of the FELs with respect to even shorter pulses, increased pulse stability, and special double-pulse schemes, e. g. for ultrafast movies [18], will open up exciting new opportunities in the field of material science. RESONANT SCATTERING FROM MAGNETIC DOMAIN SYSTEMSThe very first proof-of-principle resonant magnetic scattering experiment at x-ray FEL sources was carried out at FLASH in Hamburg [1]. In 2009 FLASH covered a photon energy range in the fundamental from 6.5 up to 50 nm with the routinely used cobalt L 3 -edge at 1.59 nm out of reach. However, by using the higher harmonics of the radiation 3 shorter wave length can be reached on the expense of photon flux. In this experiment FLASH was fine tuned to a fundamental wave length of 7.97 nm which results in the fifth harmonic located at the cobalt L 3 -edge. The scattering pattern from magnetic domains of a cobalt/palladium multilayer system with a perpendicular magnetic anisotropy and typical domain widths in the 100 nm range was recorded. This demonstrated that magnetic scattering as it is performed at synchrotron radiation sources is feasible at FELs. However, the fifth harmo...

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Direct observation of field and temperature induced domain replication in dipolar coupled perpendicular anisotropy films

Cited by 44 publications

References 14 publications

Irreversible transformation of ferromagnetic ordered stripe domains in single-shot infrared-pump/resonant-x-ray-scattering-probe experiments

Irreversible transformation of ferromagnetic ordered stripe domains in single-shot infrared-pump/resonant-x-ray-scattering-probe experiments

Exploring the limits of soft x-ray magnetic holography: Imaging magnetization reversal of buried interfaces (invited)

Ultrafast Dynamics of Magnetic Domain Structures Probed by Coherent Free-Electron Laser Light

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