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Magnetic reflectometer with high incident angle
The neutron reflectometer MARIA with polarisation analysis was designed for the investigation of thin magnetic layered structures down to the monolayer scale and lateral structures. The reflection of polarised neutrons allows to determine individually the density and the modulus and the direction of the magnetisation vector of buried layers.
MARIA is optimised for layer thicknesses between 3 – 300 Å and lateral structure sizes from nm to µm sizes. Consequently the instrument is designed for small focused beam and sample sizes of 1 cm2 at λ = 4.5 Å (available: 4.5 Å < λ < 40 Å) in a vertical orientation with a maximum incident angle of 180° and outgoing angle ranging from -14° to 100°. MARIA provides polarisation analysis in standard operation, where the beam is polarised by a polarising guide (z-geometry; 4.5 Å < λ < 10 Å ) and analysed by a wide angle 3He-cell.
Beside the above described reflectometer mode with good resolution in the horizontal scattering plane, MARIA can be used in the GISANS mode with additional resolution in the vertical direction. The latter mode allows for measuring lateral structures down to the nm scale.
At the sample position, a Hexapod with an additional turntable (360°) is installed, which can take a load up to 500 kg. In the standard configuration magnetic fields are provided up to 1.3 T (Bruker electromagnet) and cryogenic temperatures down to 4 K (He closed cycle cryostat). Beside this standard setup the complete sample environment of the JCNS can be adopted to MARIA so that magnetic fields up to 5 T and temperatures from 50 mK to 500 K are available.
All parts of MARIA are controlled by a computer system according to the “Jülich-Munich” standard based on a Linux workstation. This allows a flexible remote control with automatic scan programs, including the control of sample environment as cryostat and electromagnet.
With scattering under grazing incidence we investigate depth-resolved the laterally-averaged magnetisations and the correlations between their lateral fluctuations. With an additionally polarised neutron beam we derive a vector information on the laterally-averaged magnetisation (reflectivity) and on the correlations between their lateral fluctuations (off-specular scattering – µm length scale, GISANS – nm length scale).In general, MARIA can be used for measurements of magnetic roughness, the formation of magnetic domains in thin layered structures, lateral structures, etc. (polarised mode) and density profiles, structures of solid polymer layers, etc. (unpolarised mode with higher intensity). Furthermore possible without the need for multilayers investigation of:
Additionally the instrument in non-polarised beam mode can be used for reflectometry and GISANS studies of “soft” layers at the solid/ liquid interface by the use of appropriate liquid cells that are available at the beamline. Candidate systems for such investigations include polymer brushes, polyelectrolyte multilayers, biomimetic supported membranes, adsorbed proteins etc. For typical applications involving deuterated solvents the dynamic range that can be expected covers 7 order of magnitude.
Besides the described cryogenic temperatures and magnetic fields MARIA can provide users with a fully equipped Oxid-MBE (Molecular Beam Epitaxy). The typical sample sizes are 10 × 10 mm2 and as targets we can provide Al, Cr, Pr, Fe, La, Nb, Ag, Nd, Tb, Sr, Mn, Ti and Co.
Neutron Depth Profiling (NDP)
Alternatively to the reflectometer/GISANS mode MARIA can be operated with a multidetector Neutron Depth Profiling (NDP) setup using the focused beam. Neutron Depth Profiling allows the quantitative determination of the in-depth distribution for several light elements as 6Li, 10B, 14N and few others. In this instrument operation mode the NDP chamber is placed on the sample table, placing the NDP sample in the focal point of the vertically focusing elliptic neutron guide. The thermal equivalent neutron flux at the sample position amounts to 0.7·109 n/cm2/sec. Combined with a multiple detector system for charged particle collection it gives the opportunity to perform fast, time-resolved NDP measurements with a depth resolution of 10 nm.
Different type of solid state Li-batteries and battery materials.
Dr. Alexandros Koutsioumpas
Phone: +49 (0)89 289-11674
Dr. Kirill Zhernenkov
Phone: +49 (0)89 289-10705
Dr. Sabine Pütter
Phone: +49 (0)89 289-10742
Phone: +49 (0)89 289-10795
Neutron Depth Profiling (NDP)
Dr. Egor Vezhlev
Phone: +49 (0)89 289-11654
Find the latest publications regarding MARIA in our publication database iMPULSE:
Heinz Maier-Leibnitz Zentrum. (2015). MARIA: Magnetic reflectometer with high incident angle. Journal of large-scale research facilities, 1, A8. http://dx.doi.org/10.17815/jlsrf-1-29
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