Journal Article

FZJ-2019-00325

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Polarized neutron diffraction using a novel high-Tc superconducting magnet on the single-crystal diffractometer POLI at MLZ

Thoma, H. (First author)FZJ* ; Luberstetter, W. ; Peters, J. ; Hutanu, V. (Corresponding author)FZJ*

2018
Wiley-Blackwell [S.l.]

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Please use a persistent id in citations: doi:10.1107/S160057671800078X

Abstract: The polarized single-crystal diffractometer POLI is the first neutron scattering instrument routinely using 3 He spin filters both to produce and to analyse neutron polarization. The instrument, with a non-magnetic goniometer, was designed to perform two types of polarized neutron diffraction experiment: spherical neutron polarimetry, also known as full three-dimensional polarization analysis in zero magnetic field, and classical polarized neutron diffraction, also called the flipping-ratio (FR) method, in high applied magnetic fields. Reported here is the implementation of the FR setup for short-wavelength neutrons on POLI using a new high- T c superconducting magnet with a maximal field of 2.2 T. The complete setup consists of a 3 He polarizer, a nutator, a Mezei-type flipper, guide fields and dedicated pole pieces, together with the magnet. Each component, as well as the whole setup, was numerically simulated, optimized, built and finally successfully tested under real experimental conditions on POLI. The measured polarized neutron spin transport efficiency is about 99% at different wavelengths, e.g. as short as 0.7 Å, and up to the maximal available field of the magnet. No further depolarization of the 3 He cells due to stray fields of the magnet occurs. The additional use of the available 3 He analyser allows uniaxial polarization analysis experiments in fields up to 1.2 T. The results of the first experiment on the field-dependent distribution of the trigonal antiferromagnetic domains in haematite (α-Fe 2 O 3 ) are presented and compared with the literature data.

Keyword(s): Instrument and Method Development (1st) ; Instrument and Method Development (2nd) ; Condensed Matter Physics (2nd) ; Crystallography (2nd) ; Magnetism (2nd)

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Contributing Institute(s):

1. JCNS-FRM-II (JCNS-FRM-II)
2. Streumethoden (JCNS-2)

Research Program(s):

1. 524 - Controlling Collective States (POF3-524) (POF3-524)
2. 6G15 - FRM II / MLZ (POF3-6G15) (POF3-6G15)
3. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)
4. 6212 - Quantum Condensed Matter: Magnetism, Superconductivity (POF3-621) (POF3-621)

Experiment(s):

1. POLI: Polarized hot neutron diffractometer (SR9a)

Appears in the scientific report 2018

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Database coverage:
; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; Nationallizenz ; PubMed Central ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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