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SCIENCE AT ID32, THE SOFT X-RAY BEAMLINE
What one can do with a properly aligned beamline
Flora Yakhou-Harris Beamline Operation Manager
On behalf of the ID32 team
and our users and our support groups
Page 1 l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
WHAT SCIENCE ARE WE INTERESTED IN ? WHY SOFT X-RAYS ?
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Y Kajiwara et al. Nature 464, 262-266 (2010) doi:10.1038/nature0887
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l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
Core shells of a single atom Periodic arrays of atoms
A zoology of magnetic structures Collective excitations
SOME - VERY - USEFUL PROPERTIES OF SYNCHROTRON X-RAYS
Page 3 l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
Tunable in energy
1% ML Co on Pt
Polarized High flux
XAS XMCD
SINGLE-ATOM MAGNETS
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Fabrication and characterization of bit-patterned media beyond 1.5 Tbit/in2 Joel K W Yang et al. Nanotechnology 22, 385301 (2011)
Today Tomorrow ?
Magnetism destroyed by: Atomic vibrations (phonons)
Travelling electrons (spin scattering)
Hundreds of atoms needed to overcome disturbances
Magnetic bits limited in size and areal density
20 nm / ~1 Tbit/in2
If we can isolate atoms from disturbances
areal density
~100 Tbit/in2
Magnetic remanence in single atoms F. Donati et al. Science 352, 318 (2016) ETH Zurich / EPFL Lausanne
l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
EXPERIMENTAL REALISATION OF SINGLE-ATOM MAGNETS
Single atom magnets
Single Ho atoms
Tunneling barrier
Substrate
9 Tesla magnet for XMCD measurements
Ultra-high vacuum system used for sample growth
Experimental setup at the ID32 beamline.
In situ growth and characterization at the ESRF ID32 beamline.
A magnetic state had been written to the Ho atoms with the 9 Tesla magnet, and was then read out using XMCD.
After 30 min 32% of the atoms still retained their magnetic state, after 1 hour still more than 10%.
X-rays
XMCD vs magnetic field vs barrier thickness Magnetic remanence = open loop at zero field
Fraction of magnetic atoms vs time
XMCD signal of Ho atoms. Extremely high sensitivity is needed to measure the XMCD signal (blue).
Page 5 l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
SOME - VERY - USEFUL PROPERTIES OF SYNCHROTRON X-RAYS
They are partially coherent
They can be scattered and they interfere
Page 6 l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
They come in bunches
Fourier transform holography
Time-resolved holography
WATCHING MAGNETIC VORTICES DANCE
Page 7 l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
Magnetic domains configuration under an external static field H
RF triggered oscillations of the core H=90G
~ 500 nm
SOME - VERY - USEFUL PROPERTIES OF SYNCHROTRON X-RAYS 3
Page 8 l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
Scattering by periodic structures
Amplification at absorption edges
REXS Resonant Elastic X-ray Scattering
Energy can be transferred to the sample
Collective excitations
RIXS Resonant Inelastic X-ray Scattering
WE DO IT ALL ON ID32: A COMPLEX BEAMLINE LAYOUT
Page 9 l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
A VERY HIGH RESOLUTION MONOCHROMATOR
Page 10 l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
mλ=d(sinα+sinβ)
Length
Optics quality and groove density
Exit slit opening
Fixed exit Long input arm: 22 m Long exit arm: 35 m
A STATE-OF-THE-ART SOFT X-RAY MONOCHROMATOR
Page 11 l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
All in ultra-clean UHV 10-10 mbar
High precision mechanics: 10 nrad resolution 100 nrad, 1 μm stability Cryogenic cooling of the pre-mirror T=120 K
HOW TO ALIGN IT ?
Page 12 l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
Mechanics: PGM axis along the beam (center of entrance and exit flanges)
grating rotation axis height and orientation perpendicular to the beam
Optical elements Absolute angle of the pre-mirror
Parallelism between grating and mirror
Yaw: groove density
Roll: horizontal beam kicking
IN PRACTICE
Page 13 l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
THE CLEVER WAY IN A CLUTTERED ENVIRONMENT: THE PENTAPRISM
Page 14 l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
Mirror alignment
Pitch and roll
grating alignment
Pitch and roll
Side view
Top view
THE RIXS SPECTROMETER: ANOTHER MONOCHROMATOR
Page 15 l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
SOME ALIGNMENT ISSUES
Page 16 l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
THE HIGH RESOLUTION RIXS SPECTROMETER
Page 17 l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
Sample gratings
CCDs
Collimating mirror
Total length ~ 12 m
WHAT WILL THEY DO WITH IT?
Page 18 l IWAA 2016 l Oct 3-7 2016 Grenoble l Flora Yakhou-Harris
The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again.
ID08 (2013) ~ 250 meV FWHM
ID32 (2015) ~ 30 meV FWHM
2θ=150̊̊
2θ=90̊̊ π pol σ pol
CeCo2Ge2
A typical raw image Converted into spectra
We have provided an instrument to investigate condensed matter with very high resolution and unique features
Will physicists gain new insight into high Tc superconductivity that’s been puzzling them for the last 30 years?
Thank you !
