Time-Resolved X-Ray Magnetic Circular Dichroism — A Selective Probe of Magnetization Dynamics on Nanosecond Timescales

Pizzini, S.; Vogel, Jan; Bonfim, Marlio; Fontaine, A.

doi:10.1007/3-540-46097-7_5

“…Long term, as tomographic measurements become faster, four dimensional magnetic imaging with nanoscale resolution will become realistic. For example, a time resolved tomographic measurement could be achieved using a pump-probe measurement scheme [113][114][115][139][140][141] in which the sample is excited using current, magnetic field or laser pulses. Pump-probe stroboscopic measurements with 2D magnetic x-ray imaging are routinely used to investigate the dynamics of magnetic structures, including vortex dynamics [113,142,143], domain wall dynamics [144], and the dynamics of Bloch points [145] as well as spin waves [146].…”

Section: Technical Prospectivesmentioning

confidence: 99%

Imaging three-dimensional magnetic systems with x-rays

Donnelly

¹

,

Scagnoli

²

2020

J. Phys.: Condens. Matter

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Recent progress in nanofabrication and additive manufacturing have facilitated the building of nanometer-scale three-dimensional structures, that promise to lead to an emergence of new functionalities within a number of fields, compared to state-of-the-art two dimensional systems. In magnetism, the move to three-dimensional systems offers the possibility for novel magnetic properties not available in planar systems, as well as enhanced performance, both of which are key for the development of new technological applications. In this review paper we will focus our attention on three-dimensional magnetic systems and how their magnetic configuration can be retrieved using X-ray magnetic nanotomography. We will start with an introduction to magnetic materials, and their relevance to our everyday life, along with the growing impact that they will have in the incoming years in, for example, reducing energy consumption. We will then briefly introduce common methods used to study magnetic materials, such as electron holography, neutron and X-ray imaging. In particular, we will focus on X-ray magnetic circular dichroism and how it can be used to image magnetic moment configurations. As a next step we will introduce tomography for three-dimensional imaging, and how it can be adapted to study magnetic materials. Particular attention will be given to explaining the reconstruction algorithms that can be used to retrieve the magnetic moment configuration from the experimental data, as these represent one of the main challenges so far, as well as the different experimental geometries that are available. Recent experimental results will be used as specific examples to guide the reader through each step in order to make sure that the paper will be accessible for those interested in the topic that do not have a specialized background on magnetic imaging. Finally, we will describe the future prospects of such studies, identifying the current challenges facing the field, and how these can be tackled. In particular we will highlight the exciting possibilities offered by the next generation of synchrotron sources which will deliver diffraction limited beams, as well as with the extension of well-established methodologies currently implemented for the study of two-dimensional magnetic materials to achieve higher dimensional investigations.

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“…Long term, as tomographic measurements become faster, four dimensional magnetic imaging with nanoscale resolution will become realistic. For example, a time resolved tomographic measurement could be achieved using a pump-probe measurement scheme [138,139,140,113,112,114] in which the sample is excited using current, magnetic field or laser pulses. Pump-probe stroboscopic measurements with 2D magnetic X-ray imaging are routinely used to investigate vortex dynamics [141,142,112], domain wall dynamics [143], and the dynamics of Bloch points [144] as well as spin waves [145].…”

Section: Technical Prospectivesmentioning

confidence: 99%

Imaging three-dimensional magnetic systems with X-rays

Donnelly,

Scagnoli

2019

Preprint

0

View full text Add to dashboard Cite

Recent progress in nanofabrication and additive manufacturing have facilitated the building of nanometer-scale three-dimensional structures, that promise to lead to an emergence of new functionalities within a number of fields, compared to state-of-the-art two dimensional systems. In magnetism, the move to three-dimensional systems offers the possibility for novel magnetic properties not available in planar systems, as well as enhanced performance, both of which are key for the development of new technological applications. In this review paper we will focus our attention on three-dimensional magnetic systems and how their magnetic configuration can be retrieved using X-ray magnetic nanotomography. We will start with an introduction to magnetic materials, and their relevance to our everyday life, along with the growing impact that they will have in the incoming years in, for example, reducing energy consumption. We will then briefly introduce common methods used to study magnetic materials, such as electron holography, neutron and X-ray imaging. In particular, we will focus on X-ray magnetic circular dichroism and how it can be used to image magnetic moment configurations. As a next step we will introduce tomography for three-dimensional imaging, and how it can be adapted to study magnetic materials. Particular attention will be given to explaining the reconstruction algorithms that can be used to retrieve the magnetic moment configuration from the experimental data, as these represent one of the main challenges so far, as well as the different experimental geometries that are available. Recent experimental results will be used as specific examples to guide the reader through each step in order to make sure that the paper will be accessible for those interested in the topic that do not have a specialized background on magnetic imaging. Finally, we will describe the future prospects of such studies, identifying the current challenges facing the field, and how these can be tackled. In particular we will highlight the exciting possibilities offered by the next generation of synchrotron sources which will deliver diffraction limited beams, as well as with the extension of well-established methodologies currently implemented for the study of two-dimensional magnetic materials to achieve higher dimensional investigations.

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“…X-Ray Magnetic Circular Dichroism (XMCD) exploits the difference in absorption between left and right circularly polarized x-rays in a magnetic material [79]. In basic principle this method is the same as the Kerr or Faraday effect, but with higher energy x-rays giving access to different quantum mechanical transitions.…”

Section: Time-resolved X-ray Magnetic Circular Dichroismmentioning

confidence: 99%

Ultrafast Magnetization Dynamics of SrRuO<sub>3 </sub>Thin Films

Langner

¹

2009

0

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Itinerant ferromagnet SrRuO 3 has drawn interest from physicists due to its unusual transport and magnetic properties as well as from engineers due to its low resistivity and good lattice-matching to other oxide materials. The exact electronic structure remains a mystery, as well as details of the interactions between magnetic and electron transport properties.This thesis describes the use of time-resolved magneto-optical Kerr spectroscopy to study the ferromagnetic resonance of SrRuO 3 thin films, where the ferromagnetic resonance is initiated by a sudden change in the easy axis direction in response to a pump pulse.The rotation of the easy axis is induced by laser heating, taking advantage of a temperature-dependent easy axis direction in SrRuO 3 thin films. By measuring the change in temperature of the magnetic system in response to the laser pulse, we find that the specific heat is dominated by magnons up to unusually high temperature, ∼ 100 K, and thermal diffusion is limited by a boundary resistance between the film and the substrate that is not consistent with standard phonon reflection and scattering models.We observe a high FMR frequency, 250 GHz, and large Gilbert damping parameter, α ≈ 1, consistent with strong spin-orbit coupling. We observe a time-dependent change in the easy axis direction on a ps time-scale, and we find that parameters associated with the change in easy axis, as well as the damping parameter, have a non-monotonic temperature dependence similar to that observed in anomalous Hall measurements. Professor Joseph Orenstein Dissertation Committee Chair iFor my family ii

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Time-Resolved X-Ray Magnetic Circular Dichroism — A Selective Probe of Magnetization Dynamics on Nanosecond Timescales

Cited by 8 publications

References 56 publications

Imaging three-dimensional magnetic systems with x-rays

Imaging three-dimensional magnetic systems with x-rays

Imaging three-dimensional magnetic systems with X-rays

Ultrafast Magnetization Dynamics of SrRuO<sub>3 </sub>Thin Films

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