scholarly journals Beyond the Limits in Spectroscopy V. Core-Level Soft X-Ray Magnetic Circular Dichroism with Circularly Polarized Synchrotron Radiation.

2003 ◽  
Vol 52 (6) ◽  
pp. 377-389
Author(s):  
Tsuneharu KOIDE
Keyword(s):  
Circular Dichroism ◽  
Synchrotron Radiation ◽  
Magnetic Circular Dichroism ◽  
Core Level ◽  
Circularly Polarized ◽  
X Ray ◽  
Circular Dichroïsm

scholarly journals Magnetic Circular Dichroism in X-Ray Absorption and Core-Level Photoemission

1993 ◽  
Vol 313 ◽  
Author(s):  
J.G. Tobin ◽  
G.D. Waddill ◽  
T.H. Gouder ◽  
C.A. Colmenares ◽  
D.P. Pappas
Keyword(s):  
Circular Dichroism ◽  
Magnetic Circular Dichroism ◽  
Branching Ratio ◽  
Core Level ◽  
Magnetic Axis ◽  
X Rays ◽  
Circularly Polarized ◽  
X Ray ◽  
X Ray Absorption ◽  
Circular Dichroïsm

ABSTRACTHere is reported observation of magnetic circular dichroism in both x-ray absorption and core-level photoemission of ultra thin magnetic films using circularly polarized x-rays. Iron films (1–4 ML) grown on a Cu (001) substrate at 150 K and magnetized perpendicular to the surface show dramatic changes in the L2,3 absorption branching ratio for different x-ray polarizations. For linearly-polarized x-rays perpendicular to the magnetic axis of the sample the branching ratio was 0.75. For films ≥ 2 ML, this ratio varied from 0.64 to 0.85 for photon spin parallel and anti-parallel, respectively, to the magnetic axis. This effect was observed either by changing the x-ray helicity for a fixed magnetic axis, or by reversing the magnetic axis for a fixed x-ray helicity. Our observation can be analyzed within a simple one-electron picture, if the raw branching ratios are normalized so that the linear value becomes statistical. Furthermore, warming the films to -300 K eliminated this effect, indicating a loss of magnetization in the film over a temperature range of -30 K. Finally, reversing the relative orientation of the photon spin and the magnetic axis from parallel to anti-parallel allowed measurement with photoemission of the exchange splitting of the Fe 2p and 3p core levels which were found to be 03 eV and 0.2 eV, respectively. These results are consistent with earlier studies, but the use of off-plane circularly-polarized x-rays from a bending magnet monochromator offers -2 orders of magnitude greater intensity than typical spin-polarization measurements. Finally, we have performed preliminary x-ray absorption studies of UFe2, demonstrating the feasibilty of MCD Measurements in 5f as well as 3d Materials.

Bright Circularly Polarized Soft X-ray Harmonics for Static and Dynamic X-ray Magnetic Circular Dichroism

2016 ◽  
Author(s):  
Tingting Fan ◽  
Patrick Grychtol ◽  
Ronny Knut ◽  
Carlos Hernández-García ◽  
Daniel D. Hickstein ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Magnetic Circular Dichroism ◽  
Circularly Polarized ◽  
X Ray ◽  
Circular Dichroïsm

Crystalline symmetry effects in X-ray magnetic circular dichroism in angle-resolved core-level photoemission

1993 ◽  
Vol 5 (9) ◽  
pp. 1239-1256 ◽  
Author(s):  
D Venus ◽  
L Baumgarten ◽  
C M Schneider ◽  
C Boeglin ◽  
J Kirschner
Keyword(s):  
Circular Dichroism ◽  
Magnetic Circular Dichroism ◽  
Core Level ◽  
X Ray ◽  
Circular Dichroïsm ◽  
Crystalline Symmetry

scholarly journals X-Ray Magnetic Circular Dichroism Spectroscopy and Microscopy

MRS Bulletin ◽  
1995 ◽  
Vol 20 (10) ◽  
pp. 41-44 ◽  
Author(s):  
N.V. Smith ◽  
H.A. Padmore
Keyword(s):  
Circular Dichroism ◽  
Magnetic Circular Dichroism ◽  
X Rays ◽  
Circularly Polarized ◽  
X Ray ◽  
Insertion Device ◽  
Magnetic Circular Dichroism Spectroscopy ◽  
Out Of Plane ◽  
X Ray Absorption ◽  
Circular Dichroïsm

The advent of electron accelerators dedicated to the production of high-intensity x-rays has revitalized experimental techniques based on x-ray absorption. A recent variant is to use circularly polarized x-rays generated either by use of out-of-plane radiation from a bending magnet or from a specially designed “insertion device.” This new field of x-ray magnetic circular dichroism (XMCD) shows considerable promise in spectroscopy and microscopy of magnetic materials. In this article, we describe the nature of XMCD, offer a few examples of recent progress, and review the prospects for future development using the newly constructed Advanced Light Source (ALS).

scholarly journals Bright Circularly Polarized Soft X-Ray High Harmonics for X-Ray Magnetic Circular Dichroism

2015 ◽  
Author(s):  
Tingting Fan ◽  
Patrik Gychtol ◽  
Ronny Knut ◽  
Carlos Hernández-García ◽  
Daniel Hickstein ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Magnetic Circular Dichroism ◽  
Circularly Polarized ◽  
X Ray ◽  
High Harmonics ◽  
Circular Dichroïsm

scholarly journals Ultralow-temperature device dedicated to soft X-ray magnetic circular dichroism experiments

2018 ◽  
Vol 25 (6) ◽  
pp. 1727-1735 ◽  
Author(s):  
J.-P. Kappler ◽  
E. Otero ◽  
W. Li ◽  
L. Joly ◽  
G. Schmerber ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Circular Dichroism ◽  
Synchrotron Radiation ◽  
Eddy Current ◽  
Magnetic Circular Dichroism ◽  
X Ray ◽  
Ultralow Temperature ◽  
X Ray Absorption ◽  
Circular Dichroïsm ◽  
The Magnetic Field

A new ultralow-temperature setup dedicated to soft X-ray absorption spectroscopy and X-ray magnetic circular dichroism (XMCD) experiments is described. Two experiments, performed on the DEIMOS beamline (SOLEIL synchrotron), demonstrate the outstanding performance of this new platform in terms of the lowest achievable temperature under X-ray irradiation (T = 220 mK), the precision in controlling the temperature during measurements as well as the speed of the cooling-down and warming-up procedures. Moreover, owing to the new design of the setup, the eddy-current power is strongly reduced, allowing fast scanning of the magnetic field in XMCD experiments; these performances lead to a powerful device for X-ray spectroscopies on synchrotron-radiation beamlines facilities.

scholarly journals Bright circularly polarized soft X-ray high harmonics for X-ray magnetic circular dichroism

2015 ◽  
Vol 112 (46) ◽  
pp. 14206-14211 ◽  
Author(s):  
Tingting Fan ◽  
Patrik Grychtol ◽  
Ronny Knut ◽  
Carlos Hernández-García ◽  
Daniel D. Hickstein ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Magnetic Circular Dichroism ◽  
Single Atom ◽  
Phase Matching ◽  
Electromagnetic Spectrum ◽  
Conservation Of Energy ◽  
Circularly Polarized ◽  
X Ray ◽  
High Harmonics ◽  
Circular Dichroïsm

We demonstrate, to our knowledge, the first bright circularly polarized high-harmonic beams in the soft X-ray region of the electromagnetic spectrum, and use them to implement X-ray magnetic circular dichroism measurements in a tabletop-scale setup. Using counterrotating circularly polarized laser fields at 1.3 and 0.79 µm, we generate circularly polarized harmonics with photon energies exceeding 160 eV. The harmonic spectra emerge as a sequence of closely spaced pairs of left and right circularly polarized peaks, with energies determined by conservation of energy and spin angular momentum. We explain the single-atom and macroscopic physics by identifying the dominant electron quantum trajectories and optimal phase-matching conditions. The first advanced phase-matched propagation simulations for circularly polarized harmonics reveal the influence of the finite phase-matching temporal window on the spectrum, as well as the unique polarization-shaped attosecond pulse train. Finally, we use, to our knowledge, the first tabletop X-ray magnetic circular dichroism measurements at the N4,5 absorption edges of Gd to validate the high degree of circularity, brightness, and stability of this light source. These results demonstrate the feasibility of manipulating the polarization, spectrum, and temporal shape of high harmonics in the soft X-ray region by manipulating the driving laser waveform.

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