A new type of wide-angle supermirror analyzer of neutron polarization

Syromyatnikov, V.G.; Ul’yanov, V.A.; Lauter, Valeria; Pusenkov, V.M.; Ambaye, Haile; Goyette, R.; Hoffmann, Michael; Bulkin, A.P.; Кузнецов, Ю. Н.; Medvedev, E.

doi:10.1088/1742-6596/528/1/012021

Cited by 8 publications

(3 citation statements)

References 4 publications

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“…Based on these neutron scattering merits, PNR serves as a powerful technique to simultaneously and nondestructively characterize the chemical and magnetic nature of buried interfaces 54 . PNR experiments were performed on the Magnetism Reflectometer at the Spallation Neutron Source at Oak Ridge National Laboratory 55 – 57 , using neutrons with wavelengths λ in a band of 0.2–0.8 nm and a high polarization of 98.5–99%. Measurements were conducted in a closed-cycle refrigerator (Advanced Research System) equipped with a 1.15 T Bruker electromagnet.…”

Section: Methodsmentioning

confidence: 99%

Strain-tunable Berry curvature in quasi-two-dimensional chromium telluride

Chi

Eldred

et al. 2023

Nat Commun

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Magnetic transition metal chalcogenides form an emerging platform for exploring spin-orbit driven Berry phase phenomena owing to the nontrivial interplay between topology and magnetism. Here we show that the anomalous Hall effect in pristine Cr2Te3 thin films manifests a unique temperature-dependent sign reversal at nonzero magnetization, resulting from the momentum-space Berry curvature as established by first-principles simulations. The sign change is strain tunable, enabled by the sharp and well-defined substrate/film interface in the quasi-two-dimensional Cr2Te3 epitaxial films, revealed by scanning transmission electron microscopy and depth-sensitive polarized neutron reflectometry. This Berry phase effect further introduces hump-shaped Hall peaks in pristine Cr2Te3 near the coercive field during the magnetization switching process, owing to the presence of strain-modulated magnetic layers/domains. The versatile interface tunability of Berry curvature in Cr2Te3 thin films offers new opportunities for topological electronics.

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Section: Methodsmentioning

confidence: 99%

Strain-tunable Berry curvature in quasi-two-dimensional chromium telluride

Chi

Eldred

et al. 2023

Nat Commun

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“…The time-of-flight instrument has a polarization efficiency of 98.5%, with a wavelength band 𝜆 of 2.6-8.6 Å. Polarization analysis of the reflected and scattered beam can be performed using in situ polarized 3 He system [77][78][79] and a supermirror analyzer. [80] Using the in situ annealing capabilities of MAGREF in the available temperature range from 750 to 5 K, films were thermally annealed to well-defined intermediate states near the phase transition while being simultaneously measured with PNR. [81,82] For annealing at MAGREF, the same parameters as for ex situ treatment were applied, exposing the samples to a vacuum of 1 × 10 −6 mbar (absolute pressure) at 400 °C/ 450 °C and then cooling down to 300s and 120 K for PNR measurements.…”

Section: Methodsmentioning

confidence: 99%

La_0.6Sr_0.4CoO_3−δ Films Under Deoxygenation: Magnetic And Electronic Transitions Are Apart from The Structural Phase Transition

He,

Petracic,

Lauter

et al. 2024

Adv Funct Materials

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Topotactic phase transitions induced by changes in the oxygen vacancy concentration can largely alter the physical properties of complex oxides, including electronic and magnetic phases, while maintaining the structural integrity of the crystal lattice. An oxygen‐vacancy‐induced topotactic phase transition from perovskite (PV) to brownmillerite (BM) is achieved in epitaxial La0.6Sr0.4CoO3−δ (LSCO) thin films. Two novel intermediate states with different oxygen content are identified by X‐ray diffraction, which involves a single‐phase reduced PV state and a mixed state of co‐existing PV and BM. The combination of depth‐sensitive polarized neutron reflectometry (PNR) and Rutherford backscattering (RBS) allows a quantitative determination of magnetization and the mean oxygen content in all states, revealing a continuous transition from La0.6Sr0.4CoO2.97 to La0.6Sr0.4CoO2.5. BM formation is observed for an LSCO layer with an oxygen content of 2.67, while the magnetic and electronic transition already occurs for a layer with a higher oxygen content of 2.77 (and above) and in the absence of a BM signature. These results demonstrate that the physics of electronic metal‐to‐insulator transition (MIT), magnetic ferromagnet‐to‐non‐ferromagnet transition (FM‐to‐non‐FM), and structural PV‐to‐BM phase transition should be considered within the framework of separate but interrelated processes.

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“…With the invention of neutron guides, total reflection was applied to polarize neutron beams [21][22][23][24] which has been continued in development up to now [24][25][26][27]. Spin-up and spin-down neutrons have different widths and angles of total reflection and so can be separated.…”

Section: Introductionmentioning

confidence: 99%

Realizing a (nearly) 100% neutron beam polarization

Treimer¹,

Höppner²

2020

Meas. Sci. Technol.

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We report a neutron beam polarization P = [99.9982 ± 0.0024]%, which means an improvement of two orders of magnitude compared to known values. Actually, one can assume this neutron beam to be 100% polarized, because due to the special beam guidance the overlap of spin-up neutrons and spin-down neutrons could be suppressed down to 1.2 × 10 −12 [rel. units]. These values are about four orders of magnitude below the detection limit of a monochromatic neutron flux of 10 8 n• cm −2 s −1 .

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A new type of wide-angle supermirror analyzer of neutron polarization

Cited by 8 publications

References 4 publications

Strain-tunable Berry curvature in quasi-two-dimensional chromium telluride

Strain-tunable Berry curvature in quasi-two-dimensional chromium telluride

La_0.6Sr_0.4CoO_3−δ Films Under Deoxygenation: Magnetic And Electronic Transitions Are Apart from The Structural Phase Transition

Realizing a (nearly) 100% neutron beam polarization

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A new type of wide-angle supermirror analyzer of neutron polarization

Cited by 8 publications

References 4 publications

Strain-tunable Berry curvature in quasi-two-dimensional chromium telluride

Strain-tunable Berry curvature in quasi-two-dimensional chromium telluride

La0.6Sr0.4CoO3−δ Films Under Deoxygenation: Magnetic And Electronic Transitions Are Apart from The Structural Phase Transition

Realizing a (nearly) 100% neutron beam polarization

Contact Info

Product

Resources

About

La_0.6Sr_0.4CoO_3−δ Films Under Deoxygenation: Magnetic And Electronic Transitions Are Apart from The Structural Phase Transition