A5035764489- Magnetic and transport properties of perovskites and related materials
- Advanced Condensed Matter Physics
- Atomic and Subatomic Physics Research
- Physics of Superconductivity and Magnetism
- Shape Memory Alloy Transformations
- Multiferroics and related materials
- Quantum, superfluid, helium dynamics
- Nuclear materials and radiation effects
- Functional Brain Connectivity Studies
- Advanced MRI Techniques and Applications
- Magnetic and Electromagnetic Effects
- Nuclear Physics and Applications
- Magnetic Properties and Applications
- Plant and Biological Electrophysiology Studies
- Photoreceptor and optogenetics research
- Magnetic Properties of Alloys
- Electronic and Structural Properties of Oxides
- NMR spectroscopy and applications
- High Entropy Alloys Studies
- Advanced NMR Techniques and Applications
- Dark Matter and Cosmic Phenomena
- Geomagnetism and Paleomagnetism Studies
- Nuclear Materials and Properties
- High-pressure geophysics and materials
- Theoretical and Computational Physics
Paul Scherrer Institute
2015-2022
Physikalisch-Technische Bundesanstalt
2019-2021
Helmholtz-Zentrum Berlin für Materialien und Energie
2008-2016
Zero to Three
2012
Boise State University
2010
Technical University of Munich
2010
Abstract Upon stimulation, plants elicit electrical signals that can travel within a cellular network analogous to the animal nervous system. It is well-known in human brain, voltage changes certain regions result from concerted activity which, form of action potentials (APs), travels nerve-cell arrays. Electro- and magnetophysiological techniques like electroencephalography, magnetoencephalography, magnetic resonance imaging are used record this diagnose disorders. Here we demonstrate APs...
We report results of a new technique to measure the electric dipole moment $^{129}\mathrm{Xe}$ with $^{3}\mathrm{He}$ comagnetometry. Both species are polarized using spin-exchange optical pumping, transferred measurement cell, and transported into magnetically shielded room, where SQUID magnetometers detect free precession in applied magnetic fields. The result from one week campaign 2017 2.5 2018, combined detailed study systematic effects, is...
Abstract Inelastic X-ray scattering with meV energy resolution (IXS) is an ideal tool to measure collective excitations in solids and liquids. In non-resonant condition, the cross-section strongly dominated by lattice vibrations (phonons). However, it possible probe additional degrees of freedom such as magnetic fluctuations that are coupled phonons. The IXS spectrum system contains not only phonon dispersion but also so far undetected correlation function. Here we report observation strong...
In the high spin-orbit coupled Sr2IrO4, sensitivity of ground state to details local lattice structure shows a large potential for manipulation functional properties by inducing distortions. We use epitaxial strain modify Ir-O bond geometry in Sr2IrO4 and perform momentum-dependent Resonant Inelastic X-ray Scattering (RIXS) at metal ligand sites unveil response low energy elementary excitations. observe that pseudospin-wave dispersion tensile-strained films displays softening along [h,0]...
We report the structural and magnetic properties of $4d$ ($M$ = Rh) based $5d$ Ir) systems ${\mathrm{Ba}}_{3}{M}_{x}{\mathrm{Ti}}_{3\ensuremath{-}x}{\mathrm{O}}_{9}$ (nominally $x=0.5$, 1). The studied compositions were found to crystallize in a hexagonal structure with centrosymmetric space group $P{6}_{3}/mmc$. structures comprise ${A}_{2}{\mathrm{O}}_{9}$ polyhedra [with $A$ site (possibly) statistically occupied by $M$ Ti] which pairs transition metal ions are stacked along...
We determine the phase diagram of copper nitrate $\text{Cu}{({\text{NO}}_{3})}_{2}\ifmmode\cdot\else\textperiodcentered\fi{}2.5{\mathrm{D}}_{2}\text{O}$ in context quantum transitions and novel states matter. establish this compound as an ideal candidate to study quasi-1D Luttinger liquids, 3D Bose-Einstein-Condensation triplons, crossover between 1D physics. Magnetocaloric effect, magnetization, neutron scattering data provide clear evidence for into a liquid regime long-range ordered...
The low-temperature magnetic properties of \tcr{polycrystalline} Na$_2$IrO$_3$, a candidate material for the realization quantum spin-liquid state, were investigated by means muon-spin relaxation and nuclear resonance methods under chemical hydrostatic pressure. Li-for-Na substitution promotes an inhomogeneous order, whereas pressure (up to 3.9\,GPa) results in enhancement ordering temperature $T_\mathrm{N}$. In first case, order suggests either short- or long-range correlations broadly...
In this work, we present a new chemical route to synthesize Tm2Mn2O7 pyrochlore, which compound that is thermodynamically unstable at ambient pressure. Differently from the reported in past high-pressure synthesis of same applying oxides as starting materials, have obtained pure phase by converting TmMnO3 1100 °C and an oxygen pressure 1300 bar. The studies performed high-resolution neutron powder diffraction shown pyrochlore cubic (space group Fd3¯m) been obtained. Upon cooling below 25 K,...
Abstract Magnetic shape memory alloys (MSMAs), exhibit large strains and hence are materials, which could substitute giant magnetostrictive piezoelectrical materials in actuating devices. The actuation stress needed to induce the strain is much lower than other actuator materials. Since can be induced without phase transformation by a magnetic field, development of actuators with high working frequencies possible. However, for reasonable applications, have small fields. Up now repeatable...
The doping of the honeycomb lattice compound ${\mathrm{Na}}_{2}{\mathrm{IrO}}_{3}$ with cations having smaller ionic radius such as lithium was supposed to drive system into a Kitaev spin liquid phase. Even at smallest level long range magnetic order, present in parent compound, got suppressed evidenced by susceptibility and heat capacity measurements. At low levels, ordered phase is accompanied formation glassy state transition temperature ${T}_{F}\ensuremath{\sim}5 \mathrm{K}$ determined...
Abstract Recent developments in performance and practicality of optically-pumped magnetometers (OPMs) have enabled new capabilities non-invasive brain function mapping through magnetoencephalography. In particular, the lack cryogenic operating conditions allows for more flexible placement sensor heads closer to brain, leading improved spatial resolution source localisation capabilities. Through recording visually evoked fields (VEFs), we demonstrate that proximity can be exploited improve...
We measured the magnetic correlations in triangular lattice spin-liquid candidate material YbMgGaO$_4$ via polarized neutron diffraction. The extracted in-plane and out-of-plane components of structure factor show clear anisotropy. found that short-range persist at lowest temperature 52 mK scattering intensity is centered $M$ middle-point hexagonal Brillouin-zone edge. Moreover, we pronounced spin anisotropy, with different correlation lengths for components. When comparing to a...
Dimensionality reduction induced metal-insulator transitions in oxide heterostructures are usually coupled with structural and magnetic phase transitions, which complicate the interpretation of underlying physics. Therefore, achieving isostructural MIT is great importance for fundamental physics even more applications. Here, we report an transition driven by dimensional-crossover spin-orbital ${\mathrm{SrIrO}}_{3}$ films. By using situ pulsed laser deposition angle-resolved photoemission...
In ${\mathrm{Sr}}_{2}{\mathrm{NiIrO}}_{6}$, a metastable compound, the magnetic structure could be elucidated. The susceptibility data of compound suggests three-dimensional Heisenberg behavior. Moreover, neutron diffraction reveals novel incommensurate order, requiring exchange interactions beyond second neighbor to stabilize this phase. An propagation vector $\mathbf{k}=(0,k,k)$ with $k=0.356$ was observed in such pseudocubic system. This can an example how induce ground state and possible...
The effect of temperature dependent asymmetric line broadening is investigated in $\mathrm{Cu}({\mathrm{NO}}_{3}{)}_{2}\ifmmode\cdot\else\textperiodcentered\fi{}2.5{\mathrm{D}}_{2}\mathrm{O}$, a model material for one-dimensional bond alternating Heisenberg chain, using the high resolution neutron-resonance spin echo (NRSE) technique. Inelastic neutron scattering experiments on dispersive excitations including phase sensitive measurements demonstrate potential NRSE to resolve shapes, which...
Complex interactions in quantum magnets lead to a variety of phases with manifold correlations, which are measurable at temperatures very low compared the energy scale system. The common expectation is that effects just suppressed upon increasing temperature due additional thermal fluctuations. However, recent inelastic neutron scattering investigations one- and three-dimensional compounds indicate interplay between much more complicated. By combining high-resolution resonance spin-echo...
We report results of a new technique to measure the electric dipole moment $^{129}$Xe with $^3$He comagnetometry. Both species are polarized using spin-exchange optical pumping, transferred measurement cell, and transported into magnetically shielded room, where SQUID magnetometers detect free precession in applied magnetic fields. The result from one week campaign 2017 2.5 2018, combined detailed study systematic effects, is $d_A(^{129}\mathrm{Xe}) = (1.4 \pm 6.6_\mathrm{stat}...
We probe the spectrum of elementary excitations in SrIrO$_3$ by using heterostructured [(SrIrO$_3$)$_m$/(SrTiO$_3$)$_l$] samples to approach bulk limit. Our resonant inelastic x-ray scattering (RIXS) measurements at Ir $L_3$-edge reveal a robust low-lying collective magnetic mode with an antiferromagnetic (AF) dispersion similar insulators Sr$_2$IrO$_4$ and Sr$_3$Ir$_2$O$_7$, albeit large gap much larger linewidth. At higher energies we find spin-orbit exciton, also strongly broadened, but...
Materials showing a large magnetic field induced strain can potentially substitute giant magnetostrictive materials as well piezoelectrical ceramics in actuating devices. However the shape memory alloys face several problems for an industrial application. Besides known brittleness temperature-range is still limited due to structural and phase transition around 75°C. By alloying one of most common systems Ni-Mn-Ga with 4.8 at% 6 Cobalt Martensite temperature was increased up 422K Curie 432K....