ID08 Dragon Beamline

ID08 Users Guide

Contact Tel: +33(0)47688 +ext Nick BROOKES Scientist in charge   2439 Flora YAKHOU Beam line operator manager   2491 Júlio CRIGINSKI CEZAR Beamline Scientist   2658 ID08 Control Cabin 1   2200 ID08 Control Cabin 1   2812

Synopsis

ID08 is an intense source of polarized soft x-rays that is principally used to probe magnetism in a diverse range of systems with x-ray magneto-optical techniques and to study the electronic structure of materials using x-ray and photoelectron emission techniques. The photon energy is tunable in the range 0.3-1.6 keV making it ideal for studying the magnetic and electronic properties of transition metals and rare earths.

The beamline is equipped with:

• two APPLE II undulators providing ~100% circular/linear beam polarization
• spherical grating monochromator with an energy resolution close to DE/E=5x10-4 at 850 eV
• optics focussing down to 40 mm (FWHM) vertical beam size
• 5 different UHV experimental stations and sample preparation facilities

We can also adapt to a variety of user experimental stations.

Scientific applications

The beamline is primarily used to investigate the magnetic and electronic properties of nanoclusters, ultrathin films, superconductors and semimetals with a variety of techniques. Magneto-optical effects are particularly strong in the soft x-ray range, and can be described relatively accurately.
The research on ID08 covers a wide range of magnetic phenomena, such as spin and orbit resolved magnetic moments, magnetic anisotropies, element specific magnetisation, domain walls etc. At the same time one can study the electronic structure of materials.

Techniques Available

X-ray magnetic circular dichroism (XMCD)

The XMCD signal is the difference in the absorption of light due to a reversal of the light polarization or magnetisation. Application of sum rules allows the determination of spin, orbital moments and their anisotropies. The strong advantages of this technique are the high sensitivity (<1% of a monolayer coverage) and the element selectivity. The low temperature superconducting magnet allows application of this technique to many different aspects of new magnetic phenomena (nanomagnetism, interface spin polarization, isolated atoms on surfaces …). The magnetic field can be swept from +5 T to -5 T in the direction of the x-rays beam, in a rate of 3 T per minute. The minumum temperature on the sample is around 7 K.

Spin-polarized x-ray photoelectron spectroscopy (SPXPS)

Unraveling the spin states in photoelectron spectra provides additional information for a large class of problems. One particular application has been to combine the circular polarisation, spin resolution and absorption resonances to study high temperature superconductors. Another application is half-metallic systems.

Soft x-ray resonant magnetic scattering (SXRMS)

Soft X-Ray Resonant Magnetic Scattering (SXRMS) is a new field in condensed matter research. We have a multipurpose UHV diffractometer that can address several key issues in multilayer magnetism, manganite orbital ordering and nonmagnetic arrays by exploiting the unique capabilities of SXRMS.

Soft x-ray angle resolved and high energy resolution photoelectron spectroscopy (ARXPS)

Electronic structure studies including very high-energy resolution (~3meV analyser only) and angular resolution (~0.15deg.) are possible using the Scienta end station.

X-ray emission spectroscopy (XES)

The facilities at the beamline for carrying out XES studies are provided through a collaboration with L. Braicovich at the Politechnico in Milano. This is the Advanced X-ray emission spectrometer (AXES).