A5014467163- Advanced Condensed Matter Physics
- Magnetic and transport properties of perovskites and related materials
- Physics of Superconductivity and Magnetism
- Rare-earth and actinide compounds
- Multiferroics and related materials
- Magnetic properties of thin films
- Solid-state spectroscopy and crystallography
- Iron-based superconductors research
- Nuclear Physics and Applications
- Magnetic Properties of Alloys
- Atomic and Subatomic Physics Research
- High-pressure geophysics and materials
- Crystallization and Solubility Studies
- Topological Materials and Phenomena
- X-ray Diffraction in Crystallography
- Electronic and Structural Properties of Oxides
- Material Dynamics and Properties
- Ferroelectric and Piezoelectric Materials
- Advanced NMR Techniques and Applications
- Magnetic Properties and Applications
- Quantum, superfluid, helium dynamics
- Theoretical and Computational Physics
- Gas Sensing Nanomaterials and Sensors
- Graphene research and applications
- Ionic liquids properties and applications
Forschungszentrum Jülich
2001-2024
Institut Laue-Langevin
2014-2024
Institut Langevin
2002-2023
Ernst Ruska Centre
2004
The material class of rare earth nickelates with high Ni$^{3+}$ oxidation state is generating continued interest due to the occurrence a metal-insulator transition charge order and appearance non-collinear magnetic phases within this insulating regime. recent theoretical prediction for superconductivity in LaNiO$_3$ thin films has also triggered intensive research efforts. seems be only nickelate that stays metallic paramagnetic down lowest temperatures. So far, centimetre-sized...
The bosonic analogs of topological insulators have been proposed in numerous theoretical works, but their experimental realization is still very rare, especially for spin systems. Recently, two-dimensional (2D) honeycomb van der Waals ferromagnets emerged as a new platform excitations. Here, via comprehensive inelastic neutron scattering study and analysis the spin-wave excitations, we report magnon CrXTe
Antiferromagnetic hexagonal MnTe is a promising material for spintronic devices relying on the control of antiferromagnetic domain orientations. Here we report neutron diffraction, magnetotransport, and magnetometry experiments semiconducting epitaxial thin films together with density functional theory (DFT) calculations magnetic anisotropies. The easy axes moments within basal plane are determined to be along $\ensuremath{\langle}1\overline{1}00\ensuremath{\rangle}$ directions. spin-flop...
We report on the magnetic excitation spectrum in normal state of heavy-fermion superconductor ${\mathrm{CeCu}}_{2}{\mathrm{Si}}_{2}$ approaching quantum critical point (QCP). The response superconducting is characterized by a transfer spectral weight to energies above spin gap. In state, slowing-down quasielastic observed, which conforms scaling expected for QCP spin-density-wave type. This interpretation substantiated an analysis specific heat data and momentum dependence spectrum. Our...
An investigation of the low-temperature magnetism TmMgGaO${}_{4}$, a recently synthesized ``triangular-lattice Ising antiferromagnet,'' reveals an unconventional magnetic architecture that might arise in other similar rare-earth magnets.
The chiral components in the magnetic order multiferroic ${\text{MnWO}}_{4}$ have been studied by neutron diffraction using spherical polarization analysis as a function of temperature and external electric field. We show that sufficiently close to ferroelectric transition at $T=12.3\text{ }\text{K}$ it is possible switch component applying moderate fields constant temperature. Full hysteresis cycles can be observed which indicate strong pinning order. ${\text{MnWO}}_{4}$, furthermore,...
We have studied a ${\text{EuFe}}_{2}{\text{As}}_{2}$ single crystal by neutron diffraction under magnetic fields up to 3.5 T and temperatures down 2 K. A field-induced spin reorientation is observed in the presence of field along both $a$ $c$ axes, respectively. Above critical field, ground-state antiferromagnetic configuration ${\text{Eu}}^{2+}$ moments transforms into ferromagnetic structure with applied direction. The phase diagram for Eu sublattice presented. considerable strain...
The magnetic excitations in the cuprate superconductors might be essential for an understanding of high-temperature superconductivity. In these excitation spectrum resembles hour-glass and certain resonant within are believed to connected pairing mechanism, which is corroborated by observation a universal linear scaling superconducting gap resonance energy. So far, charge stripes widely involved physics spectra. Here we study isostructural cobaltate that also exhibits spectrum. Instead...
The magnetic structure of the Eu2+ moments in superconducting EuFe2(As1-xPx)2 sample with x = 0.19 has been determined using neutron scattering. We conclude that are aligned along c direction below T_C 19.0(1) K an ordered moment 6.6(2) mu_B state. An impurity phase similar to underdoped exists within bulk which orders antiferromagnetically T_N 17.0(2) K. found no indication iron order, nor any incommensurate order sample.
Within the last decades, it was often assumed that in hydrogen-rich disordered samples, such as proteins solution or hydrated powder form, incoherent neutron scattering from hydrogen nuclei dominated signal to an extent allowed all other contributions be neglected. As arises solely self-correlations, further justified a choice. Consequently, heavy water used contrast tool highlight molecular motions live samples. Coherent scattering, which implies many and therefore collective processes, is...
Magnetoresistance (MR) has attracted tremendous attention for possible technological applications. Understanding the role of magnetism in manipulating MR may turn steer searching new applicable materials. Here we show that antiferromagnetic (AFM) GdSi metal displays an anisotropic positive value (PMRV), up to ~415%, accompanied by a large negative thermal volume expansion (NTVE). Around TN PMRV translates negative, down ~−10.5%. Their theory-breaking magnetic-field dependencies [PMRV:...
The Neel temperature of the new frustrated family SrRE2O4 (RE = rare earth) compounds is yet limited to 0.9 K, which more or less hampers a complete understanding magnetic frustrations and spin interactions. Here we report on member family, SrTb2O4 with record TN 4.28(2) an experimental study interacting frustrating mechanisms by polarized unpolarized neutron scattering. compound displays incommensurate antiferromagnetic (AFM) order transverse wave vector Q (0.5924(1), 0.0059(1), 0) albeit...
We observe quasi-static incommensurate magnetic peaks in neutron scattering experiments on layered cobalt oxides La2-xSrxCoO4 with high Co oxidation states that have been reported to be paramagnetic. This enables us measure the excitations this highly hole-doped regime and compare our results those found low-doped exhibit hourglass spectra. The shape of completely disappears given a Sr doping. Moreover, broad low-energy are found, which not centered at peak positions but around...
We report here a comprehensive study of the AFM structures Eu and Mn magnetic sublattices as well interplay between magnetism in this compound by using both polarized non-polarized single-crystal neutron diffraction. Magnetic susceptibility, specific heat capacity measurements temperature dependence diffractions suggest that ordering moments is at 22 337 K, respectively. The ions are oriented along crystallographic $c$ axis, respective propagation vector $\textbf{k}_{Eu} = (0,0,1)$...
We report on the first single crystal study of SrTm<sub>2</sub>O<sub>4</sub>.
We report on an elastic neutron scattering study of the charge correlations in La 2– x Sr CoO 4 with = 1/3, 0.4 and 0.5. found that checkerboard ordering present 0.5 sample persist 1/3 materials. These are robust explain occurrence nano‐phase separation layered cobaltates for Sr‐concentrations away from half‐doping. The half‐integer reflections then arise nanometer‐sized hole‐rich regions (blue areas title figure) instead undoped ones (red figure). appearance is important ingredient...
We have done inelastic neutron scattering investigations of the magnetic excitations in ferromagnetic ${\mathrm{La}}_{0.7}{\mathrm{Ba}}_{0.3}{\mathrm{MnO}}_{3}$ which shows colossal magnetoresistance (CMR) behavior close to ${T}_{C}\ensuremath{\approx}350$ K. measured dispersions spin waves along $[100]$ and $[110]$ also their temperature dependence. fitted with an effective localized model get nearest-neighbor exchange interaction. shown that is no longer valid for larger momentum transfer...
We report on a unique magnetic exchange interaction in thin film of ${\text{FePt}}_{3}$, comprising an artificially created ferromagnetic (FM)/antiferromagnetic (AFM) modulation, but homogeneous chemical composition and epitaxy throughout the film. The order, other hand, is modulated resulting formation alternating FM/AFM layers. To determine existence form structure within monostoichiometric film, we use combination polarized neutron reflectometry, x-ray/neutron diffraction, conventional...
${\mathrm{Me}}_{3+\ensuremath{\delta}}\mathrm{Ge}$, being a Weyl semimetal, shows large anomalous Hall effect (AHE), which decreases slowly with an increase in $\ensuremath{\delta}$ from 0.1 to 0.4. However, AHE this compound remains significantly the whole range of because robust nature topology bands. To explore possibility tuning transport effects semimetals, we have studied single-crystal hexagonal-($\mathrm{Mn}_{0.78}\mathrm{Fe}_{0.22})_{3}\mathrm{Ge}$ compound. Magnetization two...
The tetragonal copper oxide ${\mathrm{Bi}}_{2}{\mathrm{CuO}}_{4}$ has an unusual crystal structure with a three-dimensional network of well separated ${\mathrm{CuO}}_{4}$ plaquettes. spin in the magnetically ordered state below ${T}_{\text{N}}\ensuremath{\sim}43$ K remains controversial. Here we present results detailed studies specific heat, magnetic, and dielectric properties single crystals grown by floating zone technique, combined polarized neutron scattering high-resolution x-ray...
Identifying the nature of magnetism, itinerant or localized, remains a major challenge in condensed-matter science. Purely localized moments appear only magnetic insulators, whereas more less co-exist with metallic compounds such as doped-cuprate iron-based superconductors, hampering thorough understanding role magnetism phenomena like superconductivity magnetoresistance. Here we distinguish two antiferromagnetic modulations respective propagation wave vectors $Q_{\pm}$ = ($H \pm 0.557(1)$,...