Status of the Twin Helical Undulator Soft X-ray Beamline at SPring-8: Performance for Circular Dichroism Measurements

Matsuki, Takayuki; Nakamura, Tetsuya; Matsushita, Teruo; Wakita, Takanori; Kimura, Hiroaki; Hirono, T.; Kinoshita, Toyohiko; Hara, Toru; Shirasawa, Koyo; Takeuchi, Masao; Kitamura, Hideo

doi:10.1063/1.2436125

Cited by 11 publications

(3 citation statements)

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“…The observation was performed at room temperature using the other PEEM apparatus at BL25SU, 24 where a compact PEEM apparatus (ELMITEC PEEMSPECTOR) has been installed. 25 The circularly polarized soft x-rays were incident on the sample at an angle of 30 • from the surface.…”

Section: A Experimentsmentioning

confidence: 99%

Three-dimensional spin orientation in antiferromagnetic domain walls of NiO studied by x-ray magnetic linear dichroism photoemission electron microscopy

et al. 2012

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A determination of the three-dimensional spin directions in all types of domain walls (DWs) of antiferromagnetic NiO has been successfully performed by photoemission electron microscopy combined with x-ray magnetic linear dichroism (XMLD), both for sand p-polarized light. By comparing the azimuthal angle dependence of the XMLD contrast in the DWs with cluster model calculations which include the crystal symmetry and full-multiplet splitting, we determine the spin structures in the {001} T walls, {011} T walls, 120 • S walls, and 180 • S walls. In some cases, distinct S walls are not formed between two adjacent S domains, and the spin direction changes gradually over a wide range of the S domain structures. In the S walls, the spin direction is parallel to the magnetic easy {111} plane. These spin configurations arise from the large difference in anisotropy energy between the in-plane and out-of-plane directions. Unexpectedly large widths in the several hundred nanometer range were observed for all the DWs. This also shows that NiO has a small magnetocrystalline anisotropy energy. Together with Monte Carlo simulation results, the qualitative phenomena concerning the wall energies are discussed. We further investigated the difference in wall energy between the {001} T wall and the {011} T wall. From the Monte Carlo simulation and an experimental study of heating effects, it is revealed that the {001} T wall energy is smaller than the {011} T wall energy.

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Section: A Experimentsmentioning

confidence: 99%

Three-dimensional spin orientation in antiferromagnetic domain walls of NiO studied by x-ray magnetic linear dichroism photoemission electron microscopy

et al. 2012

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“…54) The beam axes of X-rays emitted from the ID1 and ID2 are tuned to be identical within a relative positional difference of 0.5% of the FWHM of the beam width at a sample position of a photoelectron emission microscope apparatus which is installed at 79 m from the twin helical undulators sources. 55) With a helicity switching at 1 Hz by the twin helical undulators, an accuracy of the XMCD spectra was shown to be greatly improved compared to those recorded using the conventional magnetic-field-reversal technique. 40) Moreover, a measurement technique with a much higher sensitivity using a lock-in amplifier and a helicity switching at 10 Hz was developed.…”

Section: Soft-x-ray Regionmentioning

confidence: 99%

Recent Progress of the X-ray Magnetic Circular Dichroism Technique for Element-Specific Magnetic Analysis

Nakamura

Suzuki

2013

J. Phys. Soc. Jpn.

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Recent trend of the X-ray magnetic circular dichroism (XMCD) spectroscopy-based technique and the related scientific topics at SPring-8 are reviewed. At the third-generation synchrotron radiation facility, the key developments in the XMCD technique include i) significant improvements in the accuracy and sensitivity of XMCD measurements with a quick helicity switching of circularly polarized X-rays, ii) introduction of extreme conditions (strong pulsed magnetic field and high pressures), and iii) new experimental setup using the high-brilliance X-ray source (microfocusing, reflection geometry, and high-pressure cells). These achievements have effectively extended the capability of the XMCD technique, a unique magnetic probe with an element-specificity, providing fundamental scientific insights in spintronics and magnetic recording devices, magnetic nanoparticles, and magnetism under high-magnetic field and high pressures.KEYWORDS: X-ray magnetic circular dichroism, element specific magnetic hysteresis, synchrotron radiation X-rays Historical ReviewElement-specific magnetic measurements are widely recognized as a powerful experimental technique for the study of magnetic materials and have previously been exploited mainly by Mössbauer spectroscopy. For the last 30 years, an energy-tunable and polarized X-ray source at synchrotron radiation facilities has given rather expansive possibilities of element-specific magnetic measurements using X-ray spectroscopy. Indeed, X-ray magnetic circular dichroism (XMCD) spectroscopy 1,2) has become one of the leading techniques for element-specific magnetic measurement using a resonant effect in the core-shell absorption with circularly polarized X-ray photons.The XMCD effect was first observed at the Fe K edge in the hard-X-ray region in 1987 by Schütz et al.3) In their experiment, an XMCD spectrum of pure iron was obtained by reversing the direction of magnetic fields applied to a sample, and the circularly polarized X-rays were provided by the off-orbital radiation from a bending magnet (off-plane method).3) The recorded XMCD signal was quite small, of the order of ÁI=I $ 5 Â 10 À3 . Subsequently, XMCD spectra at the L 2;3 edges of rare-earth elements [4][5][6] and at the L 2;3 edges of 5d metals in some alloys with 3d transition metals were also reported. 7) XMCD measurements over a wide energy range that is similar to the extended X-ray absorption fine structure (EXAFS), called magnetic EXAFS, in Fe and Gd 3 Fe 5 O 12 showed a capability of analyses of local magnetic structures using dichroic effects. 8,9) In the soft-X-ray region, the first XMCD spectrum at the Ni L 2;3 edges in a Ni single crystal was reported by Chen et al. in 1990. 10) The circularly polarized soft X-rays were obtained by the off-plain method, similar to the previous XMCD measurement at the Fe K edge.3) The intensity of the observed XMCD signal was about 8% with respect to the resonant absorption, the so called white line, and was much larger than that recorded at the K edge. The strong XMCD value at the...

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“…15,16) In the beamline BL25SU, the helicity of circularly polarized X-rays can be periodically switched with a frequency of 0.1 Hz using kicker magnets. 17,18) The magnetic domain images were obtained from the difference between the PEEM images obtained with right and left circularly polarized lights. In the present experiment, the spatial resolution of TR-PEEM observation is less than 300 nm and the time resolution is about 100 ps.…”

Section: Experiments and Simulationmentioning

confidence: 99%

Dynamics of Magnetostatically Coupled Vortices Observed by Time-Resolved Photoemission Electron Microscopy

Arai

Okuda

Kotsugi

et al. 2011

Jpn. J. Appl. Phys.

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The dynamics of magnetostatically coupled vortices in a pair of ferromagnetic micron-sized disks has been observed in real space by pump-probe time-resolved photoemission electron microscopy. It is found that the dynamics of paired vortices is affected by a magnetic dipolar interaction. The displacement of a vortex core from its equilibrium position in the paired vortices during the supply of a magnetic field pulse is smaller than that in the isolated vortex, which is in qualitative agreement with micromagnetic simulation results. Unexpectedly, two eigenfrequencies of the paired vortices are different from each other. When the separation distance between the paired disks is shorter, the difference between the two eigenfrequencies is larger.

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Status of the Twin Helical Undulator Soft X-ray Beamline at SPring-8: Performance for Circular Dichroism Measurements

Cited by 11 publications

References 0 publications

Three-dimensional spin orientation in antiferromagnetic domain walls of NiO studied by x-ray magnetic linear dichroism photoemission electron microscopy

Three-dimensional spin orientation in antiferromagnetic domain walls of NiO studied by x-ray magnetic linear dichroism photoemission electron microscopy

Recent Progress of the X-ray Magnetic Circular Dichroism Technique for Element-Specific Magnetic Analysis

Dynamics of Magnetostatically Coupled Vortices Observed by Time-Resolved Photoemission Electron Microscopy

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