A5050252989- Advanced Condensed Matter Physics
- Physics of Superconductivity and Magnetism
- Magnetic and transport properties of perovskites and related materials
- Multiferroics and related materials
- Rare-earth and actinide compounds
- Muon and positron interactions and applications
- Electronic and Structural Properties of Oxides
- Magnetic Properties of Alloys
- Magnetic properties of thin films
- Topological Materials and Phenomena
- Superconducting Materials and Applications
- Advanced NMR Techniques and Applications
- Quantum and electron transport phenomena
- Particle physics theoretical and experimental studies
- Organic and Molecular Conductors Research
- Quantum many-body systems
- Algebraic structures and combinatorial models
- Solid-state spectroscopy and crystallography
- Plant and Fungal Species Descriptions
- Personal Information Management and User Behavior
- Magnetic Properties and Synthesis of Ferrites
- Plant and animal studies
- Magnetism in coordination complexes
- Electromagnetic wave absorption materials
- Liquid Crystal Research Advancements
Jožef Stefan Institute
2016-2025
University of Ljubljana
2022-2025
Durham University
2019-2025
Skyrmions are particlelike vortices of magnetization with nontrivial topology, which usually stabilized by Dzyaloshinskii-Moriya interactions (DMI) in noncentrosymmetric bulk materials. Exceptions centrosymmetric Gd- and Eu-based skyrmion-lattice (SL) hosts zero DMI, where both the SL stabilization mechanisms magnetic ground states remain controversial. We address these here investigating static dynamical spin properties host <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"...
Employing complementary torque magnetometry and electron spin resonance on single crystals of herbertsmithite, the closest realization to date a quantum kagome antiferromagnet featuring spin-liquid ground state, we provide novel insight into different contributions its magnetism. At low temperatures, two distinct types defects with magnetic couplings spins are found. Surprisingly, their response contradicts threefold symmetry ideal lattice, suggesting presence global structural distortion...
Centrosymmetric <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:msub><a:mi>GdRu</a:mi><a:mn>2</a:mn></a:msub><a:msub><a:mi>Si</a:mi><a:mn>2</a:mn></a:msub></a:mrow></a:math> exhibits a variety of multi-<b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mrow><b:mi>Q</b:mi></b:mrow></b:math> magnetic states as function temperature and applied field, including square skyrmion-lattice phase. The material's behavior is strongly dependent on the direction with different phase...
One of the key questions concerning frustrated lattices that has lately emerged is role disorder in inducing spin-liquid-like properties. In this context, quantum kagome antiferromagnets YCu$_3$(OH)$_6$Cl$_3$, which been recently reported as first geometrically perfect realization lattice with negligible magnetic/non-magnetic intersite mixing and a possible quantum-spin-liquid ground state, particular interest. However, contrary to previous conjectures, here we show clear evidence bulk...
The ground state of the simple Heisenberg nearest-neighbor quantum kagome antiferromagnetic model is a magnetically disordered spin liquid, yet various perturbations may lead to fundamentally different states. Here we disclose origin magnetic ordering in structurally perfect material YCu_{3}(OH)_{6}Cl_{3}, which free widespread impurity problem. Ab initio calculations and modeling its susceptibility reveal that, similar archetypal case herbertsmithite, exchange by far dominant isotropic...
The magnetic ground state of the ideal quantum kagome antiferromagnet (QKA) has been a long-standing puzzle, mainly because perturbations to nearest-neighbor isotropic Heisenberg Hamiltonian can lead various fundamentally different states. Here we investigate recently synthesized QKA representative, ${\mathrm{YCu}}_{3}{(\mathrm{OH})}_{6}{\mathrm{Cl}}_{3}$, in which commonly present real materials, like lattice distortion and intersite ion mixing, are absent. Nevertheless, this compound...
Abstract Collective behaviour of electrons, frustration induced quantum fluctuations and entanglement in materials underlie some the emergent phenomena with exotic quasi-particle excitations that are highly relevant for technological applications. Herein, we present our thermodynamic muon spin relaxation measurements, complemented by ab initio density functional theory exact diagonalization results, on recently synthesized frustrated antiferromagnet Li 4 CuTeO 6 , which Cu 2+ ions ( S = 1/2)...
Significant progress has recently been made in calculating muon stopping sites using density functional theory. The technique aims to address two of the most common criticisms muon-spin spectroscopy ($\mu^+$SR) technique, namely, where sample does stop, and what is its effect on local environment. We have designed developed a program called MuFinder that enables users carry out these calculations through simple graphical user interface (GUI). procedure for by generating initial positions,...
Diluted magnetic semiconductors possessing intrinsic static magnetism at high temperatures represent a promising class of multifunctional materials with application potential in spintronics and magneto-optics. In the hexagonal Fe-doped diluted oxide, 6H-BaTiO3-δ, room-temperature ferromagnetism has been previously reported. Ferromagnetism is broadly accepted as an property this material, despite its unusual dependence on doping concentration processing conditions. However, here reported...
The emergent behavior of spin liquids that are born out geometrical frustration makes them an intriguing state matter. We show in the quantum kagome antiferromagnet ZnCu$_3$(OH)$_6$SO$_4$ several different correlated, yet fluctuating states exist. By combining complementary local-probe techniques with neutron scattering, we discover a crossover from critical regime into gapless spin-liquid phase decreasing temperature. An additional unconventional instability latter leads to second, distinct...
Impurities, which are unavoidable in real materials, may play an important role the magnetism of frustrated spin systems with a spin-liquid ground state. We address impurity issue quantum kagome antiferromagnets by investigating ${\mathrm{ZnCu}}_{3}{(\mathrm{OH})}_{6}{\mathrm{SO}}_{4}$ (Zn-brochantite) means muon spectroscopy. show that muons dominantly couple to impurities, originating from Cu-Zn intersite disorder, and spins highly correlated spins, allowing us probe host physics via...
The ground state of the quantum kagome antiferromagnet Zn-brochantite, ${\mathrm{ZnCu}}_{3}(\mathrm{OH}{)}_{6}{\mathrm{SO}}_{4}$, which is one only a few known spin-liquid (SL) realizations in two or three dimensions, has been described as gapless SL with spinon Fermi surface. Employing nuclear magnetic resonance broad magnetic-field range down to millikelvin temperatures, we show that applied fields this enigmatic intrinsically unstable against full partial gap. A similar instability...
Temperature-dependent dynamical spin correlations, which can be readily accessed via a variety of experimental techniques, hold the potential offering unique fingerprint quantum liquids and other intriguing states. In this work we present an in-depth study temperature-dependent structure factor $S(\mathbf{q},\ensuremath{\omega})$ antiferromagnetic (AFM) Heisenberg spin-1/2 model on kagome lattice with additional Dzyaloshinskii-Moriya (DM) interactions. Using finite-temperature Lanczos method...
We present longitudinal-field muon-spin relaxation (LF $\mu$SR) measurements on two systems that stabilize a skyrmion lattice (SkL): Cu$_2$OSeO$_3$, and Co$_x$Zn$_y$Mn$_{20-x-y}$ for $(x,y)~=~(10,10)$, $(8,9)$ $(8,8)$. find the SkL phase of Cu$_2$OSeO$_3$ exhibits emergent dynamic behavior at megahertz frequencies, likely due to collective excitations, allowing be identified from $\mu$SR response. From following different cooling protocols calculations muon stopping site, we suggest...
This paper explores the influence of low-levels chemical substitution on magnetism in GaV${}_{4}$S${}_{8\ensuremath{-}y}$Se${}_{y}$. In $y$ = 0 and 0.1 materials authors use muon spin spectroscopy to reveal a gradual crossover ground state between ferromagnetic cycloidal order, with leading growth localized regions increased density. The also show, through dynamics detectable muons, that leads skyrmionic precursors over wide range temperatures.
Materials with broad absorption bands are highly desirable for electromagnetic filtering and processing applications, especially if the can be externally controlled. Here, a new class of broadband‐absorption materials is introduced. Namely, layered metamagnets exhibit an excitation continuum in magnetic‐field‐induced mixed ferro‐ antiferromagnetic phase. Employing series complementary experimental techniques involving neutron scattering, muon spin relaxation, specific heat, ac dc...
Centrosymmetric GdRu$_2$Si$_2$ exhibits a variety of multi-Q magnetic states as function temperature and applied field, including square skyrmion-lattice phase. The material's behavior is strongly dependent on the direction with different phase diagrams resulting for fields parallel or perpendicular to crystallographic $c$ axis. Here, we present results muon-spin relaxation ($\mu^+$SR) measurements single crystals GdRu$_2$Si$_2$. Our analysis based computation muon stopping sites...
Metamagnets, which exhibit a transition from low-magnetization to high-magnetization state induced by the applied magnetic field, have recently been highlighted as promising materials for controllable broadband absorption. Here we show results of multifrequency electron spin resonance (ESR) investigation Cu3Bi(SeO3)2O2Br planar metamagnet on kagome lattice. Its mixed antiferromagnetic/ferromagnetic phase is stabilized in finite range fields around 0.8 T at low temperatures and characterized...
We report the results of muon-spin spectroscopy $({\ensuremath{\mu}}^{+}\mathrm{SR})$ measurements on staggered molecular spin chain [pym-$\mathrm{Cu}{({\mathrm{NO}}_{3})}_{2}{({\mathrm{H}}_{2}\mathrm{O})}_{2}]$ (pym = pyrimidine), a material previously described using sine-Gordon field theory. Zero-field ${\ensuremath{\mu}}^{+}\mathrm{SR}$ reveals long range magnetically ordered ground state below transition temperature ${T}_{\mathrm{N}}=0.23(1)$ K. Using longitudinal-field (LF) we...
Abstract Strong quantum zero-point motion (ZPM) of light nuclei and other particles is a crucial aspect many state-of-the-art materials. However, it has only recently begun to be explored from an ab initio perspective, through several competing approximations. Here we develop unified description muon nucleus ZPM establish the regimes anharmonicity positional entanglement where different approximation schemes apply. Via density functional theory path-integral molecular dynamics simulations...
We investigate the spin-stripe mechanism responsible for peculiar nanometer modulation of incommensurate magnetic order that emerges between vector-chiral and spin-density-wave phase in frustrated zigzag spin-1/2 chain compound $\ensuremath{\beta}\ensuremath{-}{\mathrm{TeVO}}_{4}$. A combination magnetic-torque, neutron-diffraction, spherical-neutron-polarimetry measurements is employed to determine complex structures all three ordered phases. Based on these results, we develop a simple...
Abstract Elementary excitations in condensed matter capture the complex many-body dynamics of interacting basic entities a simple quasiparticle picture. In magnetic systems most established quasiparticles are magnons, collective that reside ordered spin structures, and spinons, their fractional counterparts emerge disordered, yet correlated states. Here we report on discovery elementary excitation inherent to spin-stripe order represents bound state two phason quasiparticles, resulting...