A5062276212- Rare-earth and actinide compounds
- Physics of Superconductivity and Magnetism
- Iron-based superconductors research
- Magnetic Properties of Alloys
- Semiconductor Quantum Structures and Devices
- Nuclear Materials and Properties
- High-pressure geophysics and materials
- Quantum and electron transport phenomena
- Topological Materials and Phenomena
- Advanced Condensed Matter Physics
- Magnetic and transport properties of perovskites and related materials
- Graphene research and applications
- Thermodynamic and Structural Properties of Metals and Alloys
- Inorganic Chemistry and Materials
- Superconducting Materials and Applications
- Advancements in Semiconductor Devices and Circuit Design
- Quantum, superfluid, helium dynamics
- Advanced Semiconductor Detectors and Materials
- 2D Materials and Applications
- Surface and Thin Film Phenomena
- Advanced Materials Characterization Techniques
- Magnetic properties of thin films
- Magnetic Field Sensors Techniques
- Muon and positron interactions and applications
- Radioactive element chemistry and processing
University of Amsterdam
2015-2024
Flanders Marine Institute
1995-2021
Elektrometall (Czechia)
2020
Mbarara University of Science and Technology
2019
University of Calgary
2019
Catholic University of Health and Allied Sciences
2019
Czech Academy of Sciences, Institute of Physics
2018
Vrije Universiteit Amsterdam
2004-2010
Hanoi University
2009
CEA Grenoble
2000
We report the coexistence of ferromagnetic order and superconductivity in UCoGe at ambient pressure. Magnetization measurements show that is a weak ferromagnet with Curie temperature T(C)=3 K small ordered moment m(0)=0.03 micro(B). Superconductivity observed resistive transition T(s)=0.8 for best sample. Thermal-expansion specific-heat provide solid evidence bulk magnetism superconductivity. The proximity to instability, defect sensitivity T(s), absence Pauli limiting, suggest triplet...
We studied elastic constants, ultrasonic attenuation, and ac susceptibility in a high-quality single crystal of ${\mathrm{UPt}}_{3}$ the superconducting phase. investigated coupling strain order parameter for different modes. A detailed B-T phase diagram phases obtained from elastic-constant measurements is given compared with theoretical predictions.
Abstract Recently it was demonstrated that Sr intercalation provides a new route to induce superconductivity in the topological insulator Bi 2 Se 3 . Topological superconductors are predicted be unconventional with an odd-parity pairing symmetry. An adequate probe test for is upper critical field, B c For standard BCS layered superconductor shows anisotropy when magnetic field applied parallel and perpendicular layers, but isotropic rotated plane of layers. Here we report measurements...
We report a high-pressure single crystal study of the topological superconductor Cu$_x$Bi$_2$Se$_3$. Resistivity measurements under pressure show superconductivity is depressed smoothly. At same time metallic behavior gradually lost. The upper critical field data $B_{c2}(T)$ collapse onto universal curve. absence Pauli limiting and comparison to polar state function point spin-triplet superconductivity, but an anisotropic spin-singlet cannot be discarded completely.
Whether SmB${}_{6}$ is a true Kondo insulator has been 40-year-old puzzle, as its unexpected finite low-temperature electric conductance defies that simple stereotyping. Using angle-resolved photoelectron spectroscopy, scientists find an important piece of the puzzle in material's electronic band structure, including signature topological surface conducting states.
The superconductor ${\mathrm{PdTe}}_{2}$ was recently classified as a type-II Dirac semimetal, and advocated to be an improved platform for topological superconductivity. Here, we report magnetic transport measurements conducted determine the nature of superconducting phase. Surprisingly, find that is type-I with ${T}_{c}=1.64$ K critical field ${\ensuremath{\mu}}_{0}{H}_{c}(0)=13.6$ mT. Our crystals also exhibit intermediate state demonstrated by differential paramagnetic effect. For...
Thermal-expansion and specific-heat measurements have been performed on a monocrystalline sample of U${\mathrm{Ru}}_{2}$${\mathrm{Si}}_{2}$ in the temperature region between 1.4 100 K. The thermal expansion this tetragonal compound is strongly anisotropic exhibits several anomalies investigated range. Broad are centered around 5 25 K, whereas sharp peaks thermal-expansion coefficients observed at transition to antiferromagnetic state 17.5 $\frac{c}{a}$ ratio similar dependence as...
We present measurements of the coefficients linear thermal expansion single-crystalline samples tetragonal heavy-fermion compound ${\mathrm{CeRu}}_{2}$${\mathrm{Si}}_{2}$, and its nonmagnetic analog ${\mathrm{LaRu}}_{2}$${\mathrm{Si}}_{2}$, in temperature range 1.5--270 K. The electronic part ${\mathrm{CeRu}}_{2}$${\mathrm{Si}}_{2}$ yields two distinct anomalies: (1) a huge positive contribution, caused by (antiferro)magnetic interactions between quasiparticles, centered at 9 K, (2) negative...
We report upper critical field ${B}_{c2}(T)$ measurements on a single-crystalline sample of the ferromagnetic superconductor UCoGe. ${B}_{c2}(0)$ obtained for fields applied along orthorhombic axes exceeds Pauli limit $B\ensuremath{\parallel}a,b$ and shows strong anisotropy ${B}_{c2}^{a}\ensuremath{\simeq}{B}_{c2}^{b}\ensuremath{\gg}{B}_{c2}^{c}$. This provides evidence an equal-spin pairing state superconducting gap function axial symmetry with point nodes $c$ axis, which is also direction...
We report a high-pressure single crystal study of the superconducting ferromagnet UCoGe. Ac-susceptibility and resistivity measurements under pressures up to 2.2 GPa show ferromagnetism is smoothly depressed vanishes at critical pressure $p_c = 1.4$ GPa. Near ferromagnetic point superconductivity enhanced. Upper-critical field $B_{c2}(0)$ attains remarkably large values, which provides solid evidence for spin-triplet over whole range. The obtained $p-T$ phase diagram reveals closely...
We report superconductivity at and magnetic order in the semimetallic noncentrosymmetric half-Heusler compound ErPdBi. The upper critical field, Bc2, has an unusual quasi-linear temperature variation reaches a value of 1.6 T for . Magnetic is found below Tc suppressed Since , interaction magnetism expected to give rise complex ground state. Moreover, electronic-structure calculations show that ErPdBi topologically nontrivial band inversion thus may serve as new platform study interplay...
We report a high-pressure single-crystal study of the noncentrosymmetric superconductor YPtBi (${T}_{c}=0.77$ K). Magnetotransport measurements show weak metallic behavior with carrier concentration $n\ensuremath{\simeq}2.2\ifmmode\times\else\texttimes\fi{}{10}^{19}$ cm${}^{\ensuremath{-}3}$. Resistivity up to $p=2.51$ GPa reveal superconductivity is promoted by pressure. The reduced upper critical field ${B}_{c2}(T)$ curves collapse onto single curve, values that exceed model for...
Specific-heat measurements have been performed on a single-crystalline sample of the heavy-fermion compound ${\mathrm{CeRu}}_{2}$${\mathrm{Si}}_{2}$ in strong magnetic fields up to 20 T along tetragonal axis temperature interval 1.5T30 K. The linear electronic term specific heat (\ensuremath{\gamma}) passes through pronounced maximum at field ${\mathit{B}}^{\mathrm{*}}$\ensuremath{\simeq}7.8 T, where metamagneticlike transition occurs. For above ${\mathit{B}}^{\mathrm{*}}$, mass enhancement...
We have determined the effect of hydrostatic pressure on susceptibility, ${T}^{2}$ temperature dependence spin-fluctuation resistivity, and superconductivity in ${\mathrm{UPt}}_{3}$. The ${T}_{s}$, derived from slope resistivity versus ${T}^{2}$, is used within a Fermi-liquid picture to calculate susceptibility \ensuremath{\chi} at T=0 K. depression this calculated with agrees directly measured value \ensuremath{\partial} ln\ensuremath{\chi}/\ensuremath{\partial}P=-24...
Thermal expansion measurements have been performed on single-crystalline UPt3 between 1.4 and 100K. Spin-fluctuation terms dominate the volume at low temperatures. The linear in thermal specific heat are compared a giant value is obtained for appropriate Gruneisen parameter. elastic constants of room temperature determined from sound velocity measurements. A 0.48 Mbar-1 results nearly isotropic compressibility.
The variation of the magnetic susceptibility condensed oxygen with temperature and hydrostatic pressure up to 0.6 GPa has been investigated. results yield an empirical relation between exchange parameter intermolecular distance. High-field magnetisation data on alpha -oxygen indicate a spin-flop; corresponding anisotropy agrees fairly well dipole calculations which also include prediction for direction axis. Evidence is presented long-range order in beta -oxygen.
In 3D topological insulators achieving a genuine bulk-insulating state is an important research topic. Recently, the material system (Bi,Sb)$_{2}$(Te,Se)$_{3}$ (BSTS) has been proposed as insulator with high resistivity and low carrier concentration (Ren \textit{et al.} \cite{Ren2011}). Here we present study to further refine properties of BSTS. We have synthesized Bi$_{2-x}$Sb${_x}$Te$_{3-y}$Se$_{y}$ single crystals compositions around $x = 0.5$ $y 1.3$. Resistance Hall effect measurements...
Measurements of galvanomagnetic effects in the temperature range 4.2--300 K and photoinduced ``transient thermoelectric effect'' (TTE) along ${\mathit{C}}_{2}$ axis at 300 have been made for two types solid solutions semiconductors ${\mathrm{Sb}}_{2\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{In}}_{\mathit{x}}$${\mathrm{Te}}_{3}$ (0\ensuremath{\le}x\ensuremath{\le}0.4) ${\mathrm{Sb}}_{2}$${\mathrm{Te}}_{3\mathrm{\ensuremath{-}}\mathit{y}}$${\mathrm{Se}}_{\mathit{y}}$...