WERA Beamline

The WERA beamline at ANKA is a beamline for soft X-ray spectroscopy and microscopy, owned and operated by the Institute for Solid State Physics (IFP), Forschungszentrum Karlsruhe.

Dedication, Scientific Applications
WERA provides important electron spectroscopies in the photon energy range 100 – 1500 eV and combines them in situ with photoemission microscopy. It facilitates combinatory studies of electronic and magnetic structure which have particular promise for strongly correlated, thin-film, and nanoscale materials.

Available Methods, Obtainable Parameters

Photoemission, angle-resolved photoemission, resonant photoemission (PES, ARPES, ResPES)

occupied electronic structure,
band character,
Fermi surface,
element-specific band structure

Near-edge X-ray absorption (NEXAFS):

bulk-sensitive fluorescence yield;
total and partial electron yield (unoccupied electronic structure; orbital character, occupation, crystal field strength/symmetry, and spin state; element- and site-specific information)

Photoemission electron microscopy (PEEM)

imaging of chemical and magnetic contrast;
microspectroscopy

Soft X-ray magnetic circular dichroism (SXMCD)

element-specific spin and orbital magnetic moments

Team WERA
	name	titel	e-mail
	Schuppler, Stefan	Dr.	stefan schupplerAyt1∂kit edu

WERA Aufbau

Experiment

1) Bendable refocusing mirror
2) PEEM chamber
3) Electron energy analyzer
4) Fluorescence detector
5) Chamber for pulsed-laser thin-film deposition

WERA

Energy range	100 - 1500 eV
Energy resolution (ΔE/E)	2 · 10^-4 typ.; <1 · 10^-4 demonstrated at N1s absorption edge
Source	1.5 T dipole (E_C = 6.235 keV), 10 mrad horizontal, 3 mrad vertical. •Alternative source (once transfer optics is installed): planar undulator, 20 periods, λm=10 cm (“U10”), on loan from NSRRC, Taiwan.
Optics	Astigmatic Kirkpatrick-Baez (KB) pair of front-end mirrors. Quick selection of curcular and linear polarization by aperture. Spherical grating monochromator, 3 gratings; movable entrance and exit slits. Bendable plane elliptical refocusing mirrors (KB pair) for optimum focus at sample position in all three sequential experimental stations
Sample environment	Ultrahigh vacuum (base pressure 10^-11 mbar). PES/NEXAFS chamber: sample temperature 20 – 800 K
Beam size at sample	Dipole source, PEEM chamber: typ. 0.4 mm (hor.) x 0.1 mm (vert.) FWHM
Experimental Setup	PEEM chamber: photoemission electron microscope (<100 nm resolution). PES/NEXAFS chamber: electron energy analyzer (energy resolution 2 meV, angle-resolving, 2D detection), monochromatized He lamp; fluorescence detector (4 elements, ultra-low energy); total and partial electron yield detection; LEED 3rd chamber position for SXMCD chamber or user-specific equipment

Journal papers WERA
Title	Author	Source	Date	Link
Electrostatic tuning of Kondo effect in a rare-earth-doped wide-band-gap oxide	Y. Li, R. Deng, W. Lin, Y. Tian, H. Peng, J. Yi, B. Yao, T. Wu	Phys. Rev. B 87, 155151	2013	PDF
YBa2Cu3O7/La0.7Ca0.3MnO3 bilayers: Interface coupling and electric transport properties	R. Werner, C. Raisch, A. Ruosi, B. A. Davidson, P. Nagel, M. Merz, S. Schuppler, M. Glaser, J. Fujii, T. Chassé, R. Kleiner, D. Koelle	Physical Review B 82 (2010) 224509-1-7	2010
Resonant photoemission spectroscopy studies of the magnetic phase transitions in Pr0.5Sr0.5MnO3	P. Pal, M. K. Dalai, B. R. Sekhar, I. Ulfat, M. Merz, P. Nagel, S. Schuppler	Physica B: Condensed Matter 406 (2011) 3519-3523	2011
X-ray absorption and magnetic circular dichroism of LaCoO3, La0.7Ce0.3CoO3, and La0.7Sr0.3CoO3 films: Evidence for cobalt-valence-dependent magnetism	M. Merz, P. Nagel, C. Pinta, A. Samartsev, H. von Löhneysen, M. Wissinger, S. Uebe, A. Assmann, D. Fuchs, S. Schuppler	Physical Review B 82 (2010) 174416-1-9	2010
Electronic structure of single-crystalline Sr(Fe1-xCox)2As2 probed by x-ray absorption spectroscopy: Evidence for effectively isovalent substitution of Fe2+ by Co2+	M. Merz, F. Eilers, Th. Wolf, P. Nagel, H. v. Löhneysen, S. Schuppler	Physical Review B 86 (2012) 104503-1-7	2012	PDF
Spin and orbital states in single-layered La2-xCaxCoO4 studied by doping- and temperature-dependent near-edge x-ray absorption fine structure	M. Merz, D. Fuchs, A. Assmann, S. Uebe, H. v. Löhneysen, P. Nagel, S. Schuppler	Physical Review B 84 (2011) 014436-1-9	2011
Electronic structure of the electron-doped Ca0.86Pr0.14MnO3	M. K. Dalai, P. Pal, B. R. Sekhar, M. Merz, P. Nagel, S. Schuppler, C. Martin	Physical Review B 85 (2012) 155128-1-5	2012	PDF
Structure and chemical composition of mixed benzylguanine- and methoxy-terminated self-assembled monolayers for immobilization of biomolecules	M. Bruns, C. Barth, P. Brüner, S. Engin, T. Grehl, C. Howell, P. Koelsch, P. Mack, P. Nagel, V. Trouillet, D. Wedlich, R. G. White	Surface and Interface Analysis 44 (2012) 909-913	2012	PDF
Nanoscale Order and Structure in Organic Materials: Diindenoperylene on Gold as a Model System	M. B. Casu	Crystal Growth & Design 11 (2011) 3629-3635	2011
Orbital-Resolved Partial Charge Transfer from the Methoxy Groups of Substituted Pyrenes in Complexes with Tetracyanoquinodimethane-A NEXAFS Study	K. Medjanik, D. Chercka, P. Nagel, M. Merz, S. Schuppler, M. Baumgarten, K. Müllen, S. A. Nepijko, H.-J. Elmers, G. Schönhense, H. O. Jeschke, R. Valenti	Journal of the American Chemical Society 134 (2012) 4694-4699	2012	PDF
Beyond the Heisenberg Model: Anisotropic Exchange Interaction between a Cu-Tetraazaporphyrin Monolayer and Fe3O4(100)	J. Klanke, E. Rentschler, K. Medjanik, D. Kutnyakhov, G. Schönhense, S. Krasnikov, I.V. Shvets, S. Schuppler, P. Nagel, M. Merz, H. J. Elmers	Phys. Rev. Lett. 110, 137202	2013	PDF
Ferromagnetism in Cr doped In2O3	J. B. Yi, N. N. Bao, X. Luo, H. M. Fan, T. Liu, S. Li	Thin Solid Films 531, 481-486	2013	PDF
Electronic Structure and Interface Properties of a Model Molecule for Organic Solar Cells	H. Hintz, H. Peisert, U. Aygül, F. Latteyer, I. Biswas, P. Nagel, M. Merz, S. Schuppler, D. Breusov, S. Allard, U. Scherf, T. Chassé	ChemPhysChem 11 (2010) 269-275	2010
Measurement of object height in emission electron microscopy	F. Schertz, D. Kutnyakhov, S. Schuppler, P. Nagel, S. A. Nepijko, G. Schönhense	Applied Physics A: Materials Science & Processing 102 (2011) 253-258	2011
Chloroaluminum phthalocyanine thin films: chemical reaction and molecular orientation	F. Latteyer, H. Peisert, J. Uihlein, T. Basova, P. Nagel, M. Merz, S. Schuppler, T. Chassé	Anal. Bioanal. Chem. 405, 4895-4904	2013	PDF
Magnetic Proximity Effect in YBa2Cu3O7/La2/3Ca1/3MnO3 and YBa2Cu3O7/LaMnO3+delta Superlattices	D. K. Satapathy, M. A. Uribe-Laverde, I. Marozau, V. K. Malik, S. Das, T. Wagner, C. Marcelot, J. Stahn, S. Brück, A. Rühm, S. Macke, T. Tietze, E. Goering, A. Frano, J.-H. Kim, M. Wu, E. Benckiser, B. Keimer, A. Devishvili, B. P. Toperverg, M. Merz, P. Nagel, S. Schuppler, C. Bernhard	Physical Review Letters 108 (2012) 197201-1-5	2012	PDF
Double exchange via t2g orbitals and the Jahn-Teller effect in ferromagnetic La0.7Sr0.3CoO3 probed by epitaxial strain	D. Fuchs, M. Merz, P. Nagel, R. Schneider, S. Schuppler, H. von Löhneysen	Phys. Rev. Lett. 111, 257203-1-5	2013	PDF
Photoelectron diffraction studies of Ag(001), MnO(001) and epitaxial MnO films"	A. Chassé, C. Langheinrich, M. Nagel, T. Chassé	Surface Science 605 (2011) 272-281	2011
Spectroscopic study of impurities and associated defects in nanodiamonds from Efremovka (CV3) and Orgueil (CI) meteorites	A. A. Shiryaev, A. V. Fisenko, I. I. Vlasov, L. F. Semjonova, P. Nagel, S. Schuppler	Geochimica et Cosmochimica Acta 75 (2011) 3155-3165	2011