Mimicking the hair surface for neutron reflectometry.

The surface of human hair is normally hydrophobic as it is covered by a lipid layer, mainly composed of 18-methyleicosanoic acid (18-MEA). When the hair is damaged, this layer can be partially or fully removed and more hydrophilic, mainly negatively charged surfaces are formed with a wide variety of physical and chemical characteristics. The cosmetic industry is currently embracing the opportunity of increasing the sustainability of their hair-care products whilst improving product performance.

Observation by SANS and PNR of pure Néel-type domain wall profiles and skyrmion suppression below room temperature in magnetic [Pt/CoFeB/Ru] multilayers.

We report investigations of the magnetic textures in periodic multilayers [Pt(1 nm)/(CoFeB(0.8 nm)/Ru(1.4 nm)] using polarised neutron reflectometry (PNR) and small-angle neutron scattering (SANS).

Realization of an advanced super-mirror solid-state neutron polarizer for the instrument PF1B at the Institut Laue-Langevin.

In this last of a series of three papers on the development of an advanced solid-state neutron polarizer, we present the final construction of the polarizer and the results of its commissioning. The polarizer uses spin-selective reflection of neutrons by interfaces coated with polarizing super-mirrors. The polarizer is built entirely in-house for the PF1B cold neutron beam facility at the Institut Max von Laue-Paul Langevin (ILL).

Reversible exchange bias in epitaxial VO/Ni hybrid magnetic heterostructures.

In this work we present a temperature and angular dependent study of the structural and magnetic properties in highly crystalline VO/Ni/Zr magnetic heterostructure films. Our investigation focuses on the coupling between the ferromagnetic Ni layer and VOlayer which undergoes an antiferromagnetic/paramagnetic phase transition coupled to the structural phase transition of the material at around 150 K. Structural investigations using x-ray diffraction reveal highly crystalline films of a quality which has previously not been reported in the literature.

Emergent Magnetic Fan Structures in Manganite Homojunction Arrays.

Devices with tunable magnetic noncollinearity are important components of superconducting electronics and spintronics, but they typically require epitaxial integration of several complex materials. The spin-polarized neutron reflectometry measurements on La Sr MnO homojunction arrays with modulated Sr concentration reported herein have led to the discovery of magnetic fan structures with highly noncollinear alignment of Mn spins and an emergent periodicity twice as large as the array's unit cell. The neutron data show that these magnetic superstructures can be fully long-range ordered, despite the gradual modulation of the doping level created by charge transfer and chemical intermixing.

Crystal structure, hydrogen bonds and thermal transformations of superprotonic conductor Cs(SO)(HPO).

Crystals of Cs(SO)(HPO) belong to the family of alkali metal acid salts that show a high protonic conductivity at relatively low temperatures. Such properties make superprotonic crystals an excellent choice for the study of the influence of the hydrogen subsystem on the physicochemical properties and promising materials for energy-efficient technologies. Single crystals of Cs(SO)(HPO) were studied by neutron diffraction methods, optical polarization microscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy.

Graphite intercalation compound (GIC) crystal monochromators for cold neutron instruments: Characterization of KC by time-of-flight neutron diffraction.

Graphite intercalation compounds (GICs) are a group of layered materials that are suitable as monochromators for cold neutrons. KC is a particularly interesting compound in this regard as it features a large c-axis lattice spacing of 8.74 Å, high reflectivity, and the possibility to produce large crystals with mosaicity that matches the beam divergence of cold neutron guides.

Magnetic and Electronic Properties of Weyl Semimetal CoMnGa Thin Films.

Magnetic Weyl semimetals are newly discovered quantum materials with the potential for use in spintronic applications. Of particular interest is the cubic Heusler compound CoMnGa due to its inherent magnetic and topological properties. This work presents the structural, magnetic and electronic properties of magnetron co-sputtered CoMnGa thin films, with thicknesses ranging from 10 to 80 nm.

Nuclear Spin Incoherent Neutron Scattering from Quantum Well Resonators.

We report the detection and quantification of nuclear spin incoherent scattering from hydrogen occupying interstitial sites in a thin film of vanadium. The neutron wave field is enhanced in a quantum resonator with magnetically switchable boundaries. Our results provide a pathway for the study of dynamics at surfaces and in ultrathin films using inelastic and/or quasielastic neutron scattering methods.

The viscoelastic signature underpinning polymer deformation under shear flow.

Entangled polymers are deformed by a strong shear flow. The shape of the polymer, called the form factor, is measured by small angle neutron scattering. However, the real-space molecular structure is not directly available from the reciprocal-space data, due to the phase problem.

Neutron reflectometry on highly absorbing films and its application to BC-based neutron detectors.

Neutron reflectometry is a powerful tool used for studies of surfaces and interfaces. The absorption in the typical studied materials is neglected and this technique is limited only to the reflectivity measurement. For strongly absorbing nuclei, the absorption can be directly measured by using the neutron-induced fluorescence technique which exploits the prompt particle emission of absorbing isotopes.

Polarized neutron reflectivity from monolayers of self-assembled magnetic nanoparticles.

We prepared monolayers of iron oxide nanoparticles via self-assembly on a bare silicon wafer and on a vanadium film sputter deposited onto a plane sapphire substrate. The magnetic configuration of nanoparticles in such a dense assembly was investigated by polarized neutron reflectivity. A theoretical model fit shows that the magnetic moments of nanoparticles form quasi domain-like configurations at remanence.

SuperADAM: upgraded polarized neutron reflectometer at the Institut Laue-Langevin.

A new neutron reflectometer SuperADAM has recently been built and commissioned at the Institut Laue-Langevin, Grenoble, France. It replaces the previous neutron reflectometer ADAM. The new instrument uses a solid state polarizer/wavelength filter providing a highly polarized (up to 98.

Magnetic proximity effect in YBa2Cu3O7/La(2/3)Ca(1/3)MnO3 and YBa2Cu3O7/LaMnO(3+δ) superlattices.

Using neutron reflectometry and resonant x-ray techniques we studied the magnetic proximity effect (MPE) in superlattices composed of superconducting YBa2Cu3O7 and ferromagnetic-metallic La0.67Ca0.33MnO3 or ferromagnetic-insulating LaMnO(3+δ).

Self-assembled iron oxide nanoparticle multilayer: x-ray and polarized neutron reflectivity.

We have investigated the structure and magnetism of self-assembled, 20 nm diameter iron oxide nanoparticles covered by an oleic acid shell for scrutinizing their structural and magnetic correlations. The nanoparticles were spin-coated on an Si substrate as a single monolayer and as a stack of 5 ML forming a multilayer. X-ray scattering (reflectivity and grazing incidence small-angle scattering) confirms high in-plane hexagonal correlation and a good layering property of the nanoparticles.

Magnetic structure of GdCu(6).

Hot neutron diffraction has been used to study the magnetic structure of GdCu(6). Long range antiferromagnetic order with a propagation vector of (h 0 0) has been determined below the Néel temperature T(N) = 16 K from the neutron powder refinement. The magnetic moments are oriented normal to the a direction, which is in agreement with previously reported results of bulk experiments.