This title appears in the Scientific Report :
2019
A transfer chamber for polarized neutron reflectometry on thin films under UHV conditions
A transfer chamber for polarized neutron reflectometry on thin films under UHV conditions
A transfer chamber for polarized neutron reflectometry on thin films under UHV conditionsS. Pütter*,1, A. Syed Mohd1, S. Mattauch1, A. Koutsioubas1, and T. Brückel21. Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ) Forschungszentrum Jülich GmbH, Garching, Germany2. Jül...
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Personal Name(s): | Pütter, Sabine (Corresponding author) |
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Syed Mohd, Amir / Mattauch, Stefan / Koutsioumpas, Alexandros / Brückel, Thomas | |
Contributing Institute: |
Streumethoden; JCNS-2 JCNS-FRM-II; JCNS-FRM-II |
Imprint: |
2019
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Conference: | Second NFFA Europe Science Workshop, Milan (Italy), 2019-02-20 - 2019-02-21 |
Document Type: |
Poster |
Research Program: |
Quantum Condensed Matter: Magnetism, Superconductivity Controlling Collective States FRM II / MLZ Jülich Centre for Neutron Research (JCNS) |
Subject (ZB): | |
Publikationsportal JuSER |
A transfer chamber for polarized neutron reflectometry on thin films under UHV conditionsS. Pütter*,1, A. Syed Mohd1, S. Mattauch1, A. Koutsioubas1, and T. Brückel21. Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ) Forschungszentrum Jülich GmbH, Garching, Germany2. Jülich Centre for Neutron Science and Peter Grünberg Institut, JCNS-2/PGI-4: Quantum Materials and Collective Phenomena, Forschungszentrum Jülich GmbH, Jülich, Germany*s.puetter@fz-juelich.deWithin JRA 5 of the NFFA project we have designed and fabricated a versatile small ultra high vacuum (UHV) chamber which can be used for sample transfer and measurement at the polarized neutron reflectometer MARIA of the Jülich Centre for Neutron Science (JCNS) at the Heinz Maier-Leibnitz Zentrum in Garching, Germany and elsewhere. [1]We were motivated by the problem that the investigation of ultrathin films which are sensitive to ambient air is a challenge at large scale instruments as the capabilities for on-site growth UHV chambers to measure in-situ are limited, mostly due to lacking space. A common workaround is the use of protecting cap layers on top of the thin film. However, cap layers may change the physical properties of the sample [2].The samples are prepared in the JCNS thin film laboratory by molecular beam epitaxy and moved into the compact chamber for transfer to the nearby reflectometer MARIA. The transfer chamber is based on a DN 40 cube equipped with sapphire windows, an SAES getter pump and a wobble stick, which serves also as a sample holder for samples of up to 1 cm2. The pressure in the transfer chamber is kept in the 10−10 mbar range during transport and measurement. The chamber fits perfectly into the magnet of the reflectometer. Polarized neutron reflectivity (PNR) measurements can be performed at room temperature and in magnetic fields in the sample plane of up to 300 mT.Fig. 1: Photo of the transfer chamber (W. Schürmann) For testing the chamber Co thin films were deposited on Pt buffered MgO(001) substrates with the MBE system and transfered to MARIA. PNR measurements of these films were performed first under UHV condition and then after exposing to ambient air. The fitting of the PNR data shows that the surface of the Co film oxidizes in air but remains free from contamination in the UHV transport chamber.Second we varied the Co film thickness to study the magnetic moment by PNR. The results reveal the vertical depth profile of the magnetic moment of the Co films. The magnetisation is not constant but smeared out at the edges, due to roughness and intermixing. We find an evolution of the magnetic moment of Co which may be separated in a bulk and a surface contribution.The transfer chamber is offered within the NFFA project to users who want to perform PNR measurements and sample preparation with the MBE system. This project has received funding from the EU’s H2020 research and innovation programme under grant agreement n. 654360.References:[1] A. Syed Mohd, S. Pütter, S. Mattauch, A. Koutsioubas, H. Schneider, A. Weber, and T. Brückel, “A versatile UHV transport and measurement chamber for neutron reflectometry under UHV conditions”, Rev. Sci. Instrum., vol. 87, pp. 123909, 2016[2] F. El Gabaly, K. F. McCarty, A. K. Schmid, J. de la Figuera, M. C. Muñoz, L. Szunyogh, P. Weinberger, and S. Gallego,”Noble metal capping effects on the spin-reorientation transitions of Co/Ru(0001)”, New J. Phys., vol. 10, pp. 073024, 2008 |