Optical determination of the Néel vector in a CuMnAs thin-film antiferromagnet

Recent breakthroughs in electrical detection and manipulation of antiferromagnets have opened a new avenue in the research of non-volatile spintronic devices.1-10 Antiparallel spin sublattices in antiferromagnets, producing zero dipolar fields, lead to the insensitivity to magnetic field perturbations, multi-level stability, ultrafast spin dynamics and other favorable characteristics which may find utility in fields ranging from magnetic memories to optical signal processing. However, the absence of a net magnetic moment and the ultra-short magnetization dynamics timescales make antiferromagnets notoriously difficult to study by common magnetometers or magnetic resonance techniques. In this paper we demonstrate the experimental determination of the Néel vector in a thin film of antiferromagnetic CuMnAs9,10 which is the prominent material used in the first realization of antiferromagnetic memory chips.10 We employ a femtosecond pump-probe magneto-optical experiment based on magnetic linear dichroism. This table-top optical method is considerably more accessible than the traditionally employed large scale facility techniques like neutron diffraction11 and Xray magnetic dichroism measurements.12-14 This optical technique allows an unambiguous direct determination of the Néel vector orientation in thin antiferromagnetic films utilized in devices directly from measured data without fitting to a theoretical model

Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 1: The LBNF and DUNE Projects

This document presents the Conceptual Design Report (CDR) put forward by an international neutrino community to pursue the Deep Underground Neutrino Experiment at the Long-Baseline Neutrino Facility (LBNF/DUNE), a groundbreaking science experiment for long-baseline neutrino oscillation studies and for neutrino astrophysics and nucleon decay searches. The DUNE far detector will be a very large modular liquid argon time-projection chamber (LArTPC) located deep underground, coupled to the LBNF multi-megawatt wide-band neutrino beam. DUNE will also have a high-resolution and high-precision near detector

Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report, Volume 4 The DUNE Detectors at LBNF

A description of the proposed detector(s) for DUNE at LBN

Soft-X-ray magneto-optical Faraday effect on

The magneto-optical Faraday effect on \chem{Fe} and \chem{Co} thin films was measured by analysing the polarisation of the transmitted synchrotron radiation. The effect was investigated as a function of photon energy, angle of incidence and magnetic-field strength. Strong influences of the sample thickness, protective layer and the type of support membrane were observed. At the 2p absorption edges, resonantly enhanced rotation values of up to $2.3 \times 10^5$ \un{degrees/mm} were found which are one order of magnitude larger than in the visible range. This suggests a new modulation technique for polarisation-sensitive spectroscopy and high-resolution microscopy experiments on anti-ferromagnetic materials

Layer-selective magnetization reversal in GMR layer systems

IrMn-based spin-valve systems with CoFe and CoFe/FeNi combinations serving as hard and soft magnetic layers, respectively, were investigated by polarized soft X-ray scattering at photon energies close to the L absorption edges of the constituent elements. Structural and magnetic information was obtained making use of the XMCD (X-ray magnetic circular dichroism) technique in reflection. Hysteresis loops of the individual layers in the spin-valve system were measured element-selectively by tuning the incidence angle of the radiation, opening the possibility of magnetic depth profiling. (C) 2003 Elsevier B.V. All rights reserved

Soft X-ray magnetic circular dichroism in Fe and Fe

Magnetic circular dichroism (MCD) in X-ray absorption has been measured at the ${\rm L}_{2,3}$ edges of Fe in ex-situ grown Fe and ${{\rm Fe}_{0.50}{\rm Co}_{0.48}{\rm V}_{0.02}}$ films by means of the transmission method. A new approach is developed for fitting the observed transmittance, which describes the resonance lineshapes as (generalized) Fano profiles. Analytical integration of each single resonance allows a more reliable determination of the orbital and spin magnetic moments based on the MCD sum rules. The results are consistent with an increase of the Fe spin and orbital magnetic moment in Fe-Co alloys as obtained by other experiments and band structure calculations

Magnetic order in Co/Cu multilayers studied by polarized soft X-rays and neutrons

The magnetic coupling in Co/Cu multilayers with individual layer thicknesses tuned to the 2nd maximum of the giant magnetoresistance (GMR) is investigated by soft X-ray magnetic scattering. A series of half-integer order magnetic peaks appears in the specularly scattered intensity especially with the higher orders being strongly sensitive to magnetic effects. Diffuse magnetic scattering, performed with polarized neutrons, indicates long-range magnetic correlation in the remanent multilayer state and a corresponding magnetic domain structure sensitive to the magnetic field applied before. (C) 2004 Elsevier B.V. All rights reserved

Direct observation of local ferromagnetism on carbon in

An element-selective investigation of magnetism on carbon in the vicinity of \chem{Fe} atoms in a \chem{C/Fe} multilayer is reported. We utilize resonant magnetic reflectivity of circularly polarized synchrotron radiation which allows us to distinguish unambiguously the local magnetism on carbon from that on \chem{Fe} through individual core-level excitations. Clear magnetic signals of carbon are obtained by exploiting the standing-wave technique. Hysteresis loops of individually excited \chem{C} and \chem{Fe} atoms demonstrate ferromagnetism of \chem{C} at room temperature with a moment of \approx 0.05{\mu_\ab{B}} induced by adjacent \chem{Fe} atoms