Comparison of time-of-flight and MIEZE neutron spectroscopy of HO.

We report a comparison of modulation of intensity with zero effort (MIEZE), a neutron spin-echo technique, and neutron time-of-flight (ToF) spectroscopy, a conventional neutron scattering method. The evaluation of the respective recorded signals, which can be described by the intermediate scattering function (, τ) (MIEZE) and the dynamic structure factor (, ) (ToF), involves a Fourier transformation that requires detailed knowledge of the detector efficiency, instrumental resolution, signal background and range of validity of the spin-echo approximation. It is demonstrated that data obtained from pure water align well within the framework presented here, thereby extending the applicability of the MIEZE technique beyond the spin-echo approximation and emphasizing the complementarity of the two methods.

Extending MIEZE spectroscopy towards thermal wavelengths.

A modulation of intensity with zero effort (MIEZE) setup is proposed for high-resolution neutron spectroscopy at momentum transfers up to 3 Å, energy transfers up to 20 meV and an energy resolution in the microelectronvolt range using both thermal and cold neutrons. MIEZE has two prominent advantages compared with classical neutron spin echo. The first is the possibility to investigate spin-depolarizing samples or samples in strong magnetic fields without loss of signal amplitude and intensity.

Using small-angle scattering to guide functional magnetic nanoparticle design.

Magnetic nanoparticles offer unique potential for various technological, biomedical, or environmental applications thanks to the size-, shape- and material-dependent tunability of their magnetic properties. To optimize particles for a specific application, it is crucial to interrelate their performance with their structural and magnetic properties. This review presents the advantages of small-angle X-ray and neutron scattering techniques for achieving a detailed multiscale characterization of magnetic nanoparticles and their ensembles in a mesoscopic size range from 1 to a few hundred nanometers with nanometer resolution.

Robust approaches for model-free small-angle scattering data analysis.

The small-angle neutron scattering data of nanostructured magnetic samples contain information regarding their chemical and magnetic properties. Often, the first step to access characteristic magnetic and structural length scales is a model-free investigation. However, due to measurement uncertainties and a restricted range, a direct Fourier transform usually fails and results in ambiguous distributions.

Yu-Shiba-Rusinov bands in ferromagnetic superconducting diamond.

The combination of different exotic properties in materials paves the way for the emergence of their new potential applications. An example is the recently found coexistence of the mutually antagonistic ferromagnetism and superconductivity in hydrogenated boron-doped diamond, which promises to be an attractive system with which to explore unconventional physics. Here, we show the emergence of Yu-Shiba-Rusinov (YSR) bands with a spatial extent of tens of nanometers in ferromagnetic superconducting diamond using scanning tunneling spectroscopy.

The influence of phonon softening on the superconducting critical temperature of Sn nanostructures.

The increase in superconducting transition temperature (T) of Sn nanostructures in comparison to bulk, was studied. Changes in the phonon density of states (PDOS) of the weakly coupled superconductor Sn were analyzed and correlated with the increase in T measured by magnetometry. The PDOS of all nanostructured samples shows a slightly increased number of low-energy phonon modes and a strong decrease in the number of high-energy phonon modes in comparison to the bulk Sn PDOS.

Enhanced Magnetoelectric Coupling in BaTiO-BiFeO Multilayers-An Interface Effect.

Combining various (multi-)ferroic materials into heterostructures is a promising route to enhance their inherent properties, such as the magnetoelectric coupling in BiFeO3 thin films. We have previously reported on the up-to-tenfold increase of the magnetoelectric voltage coefficient α ME in BaTiO3-BiFeO3 multilayers relative to BiFeO3 single layers. Unraveling the origin and mechanism of this enhanced effect is a prerequisite to designing new materials for the application of magnetoelectric devices.

Impact of magnetization and hyperfine field distribution on high magnetoelectric coupling strength in BaTiO-BiFeO multilayers.

Correlations were established between the hyperfine field distribution around the Fe atoms, the multiferroic properties, and the high magnetoelectric coefficient in BaTiO-BiFeO multilayer stacks with variable BiFeO single layer thickness, down to 5 nm. Of key importance in this study was the deposition of Fe - enriched BiFeO, which enhances the sensitivity of conversion electron Mössbauer spectroscopy by orders of magnitude. The magnetoelectric coefficient α reaches a maximum of 60.

Tunability of Size and Magnetic Moment of Iron Oxide Nanoparticles Synthesized by Forced Hydrolysis.

To utilize iron oxide nanoparticles in biomedical applications, a sufficient magnetic moment is crucial. Since this magnetic moment is directly proportional to the size of the superparamagnetic nanoparticles, synthesis methods of superparamagnetic iron oxide nanoparticles with tunable size are desirable. However, most existing protocols are plagued by several drawbacks.

Superconducting Ferromagnetic Nanodiamond.

Superconductivity and ferromagnetism are two mutually antagonistic states in condensed matter. Research on the interplay between these two competing orderings sheds light not only on the cause of various quantum phenomena in strongly correlated systems but also on the general mechanism of superconductivity. Here we report on the observation of the electronic entanglement between superconducting and ferromagnetic states in hydrogenated boron-doped nanodiamond films, which have a superconducting transition temperature T ∼ 3 K and a Curie temperature T > 400 K.