Henrik Moodysson Rønnow

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

Establishing the physical mechanism governing exchange interactions is fundamental for exploring exotic phases such as quantum spin liquids in real materials. In this Letter, we address exchange interactions in Sr2CuTexW1-xO6, a series of double perovskite ...

We have used exact numerical diagonalization to study the excitation spectrum and the dynamic spin correlations in the s = 1/2 next-next-nearest-neighbor Heisenberg antiferromagnet on the square lattice, with additional four-spin ring exchange from higher- ...

Magnetic topological insulators and semimetals are a class of crystalline solids whose properties are strongly influenced by the coupling between non-trivial electronic topology and magnetic spin configurations. Such materials can host exotic electromagnet ...

One of the simplest quantum many-body systems is the spin-1/2 Heisenberg antiferromagnetic chain, a linear array of interacting magnetic moments. Its exact ground state is a macroscopic singlet entangling all spins in the chain. Its elementary excitations, ...

We report neutron diffraction studies of the magnetic structure in BaTiOCu4(PO4)4 , which is a newly discovered magneticinsulator crystallizing in a tetragonal chiral crystal structure with P4212 space group [1]. The crystal structure ischaracterized by an ...

We report on the commissioning results of the cold neutron multiplexing secondary spectrometer CAMEA (Continuous Angle Multi -Energy Analysis) at the Swiss Spallation Neutron Source at the Paul Scherrer Institut, Switzerland. CAMEA is optimized for efficie ...

The spin-gap evolution upon Ca doping in Sr14-xCaxCu24O41 was systematically investigated using inelastic neutron scattering. We discover that the singlet-triplet spin-gap excitation survives in this series with x up to 13, indicating the singlet dimer gro ...

The discovery of a novel long-lived metastable skyrmion phase in the multiferroic insulator Cu2OSeO3 visualized with Lorentz transmission electron microscopy for magnetic fields below the equilibrium skyrmion pocket is reported. This phase can be accessed ...

The suppression of magnetic order with pressure concomitant with the appearance of pressure-induced superconductivity was recently discovered in CrAs. Here we present a neutron diffraction study of the pressure evolution of the helimagnetic ground state to ...

Quantum magnetic materials can provide explicit realizations of paradigm models in quantum many-body physics. In this context, SrCu2(BO3)2 is a faithful realization of the Shastry-Sutherland model for ideally frustrated spin dimers, even displaying several ...

Quantum fluctuations in low-dimensional systems and near quantum phase transitions have significant influences on material properties. Yet, it is difficult to experimentally gauge the strength and importance of quantum fluctuations. Here we provide a reson ...

High-resolution neutron inelastic scattering experiments in applied magnetic fields have been performed on La1.895Sr0.105CuO4 (LSCO). In zero field, the temperature dependence of the low-energy peak intensity at the incommensurate momentum transfer Q(IC)=( ...

In the Ca1-xLaxFeAs2 (1 1 2) family of pnictide superconductors, we have investigated a highly overdoped composition (x = 0.56), prepared by a high-pressure, high-temperature synthesis. Magnetic measurements show an antiferromagnetic transition at T-N = 12 ...

Iron based high temperature superconductors have several common features with superconducting cuprates, including the square lattice and the proximity to an antiferromagnetic phase. The magnetic excitation spectrum below T-c of Fe1.02Te0.7Se0.3 shows an ho ...

Quantum magnets have occupied the fertile ground between many-body theory and low-temperature experiments on real materials since the early days of quantum mechanics. However, our understanding of even deceptively simple systems of interacting spin-1/2 par ...

We present a method to directly visualise a statistical analysis of skyrmion defect alignment at grain boundaries in the skyrmion host Cu2OSeO3. Using Lorentz transmission electron microscopy, we collected large data sets with several hundreds of frames co ...

The magnetic and structural properties of polycrystalline Co4-xNixNb2O9 (x = 1, 2) have been investigated by neutron powder diffraction, magnetization and heat capacity measurements, and density functional theory (DFT) calculations. For x = 1, the compound ...

The magnetic structure and electronic ground state of the layered perovskite Ba2IrO4 have been investigated using x-ray resonant magnetic scattering. Our results are compared with those for Sr2IrO4, for which we provide supplementary data on its magnetic s ...

Uniquely in Cu2OSeO3, the Skyrmions, which are topologically protected magnetic spin vortexlike objects, display a magnetoelectric coupling and can be manipulated by externally applied electric (E) fields. Here, we explore the E-field coupling to the magne ...

Sr2CuTeO6 presents an opportunity for exploring low-dimensional magnetism on a square lattice of S = 1/2 Cu2+ ions. We employ ab initio multireference configuration interaction calculations to unravel the Cu2+ electronic structure and to evaluate exchange ...

Henrik Moodysson Rønnow

Chat with Graph Search

Exchange Interactions Mediated by Nonmagnetic Cations in Double Perovskites

Exact diagonalization study of the Hubbard-parametrized four-spin ring exchange model on a square lattice

Understanding unconventional magnetic order in a candidate axion insulator by resonant elastic x-ray scattering

Fractional spinon excitations in the quantum Heisenberg antiferromagnetic chain

Magnetic quadrupolar order in the chiral square cupola compound BaTiOCu4(PO4)4

Commissioning of the novel Continuous Angle Multi-energy Analysis spectrometer at the Paul Scherrer Institut

Spin-gap evolution upon Ca doping in the spin-ladder series Sr(14−x)CaxCu24O41 studied by inelastic neutron scattering

Light-Induced Metastable Hidden Skyrmion Phase in the Mott Insulator Cu2OSeO3

Pressure dependence of the magnetic order in CrAs: A neutron diffraction investigation

Spin Waves and Three Dimensionality in the High-Pressure Antiferromagnetic Phase of SrCu2 (BO3)2

Magnon interactions in a moderately correlated Mott insulator

Magnetic-field-induced spin excitations and renormalized spin gap of the underdoped La1.895Sr0.105CuO4 superconductor

Persistent antiferromagnetic order in heavily overdoped Ca1-xLaxFeAs2

Pressure induced evolution of superconductivity and magnetic hourglass dispersion in Fe1.02Te0.7Se0.3

Fractional excitations in the square-lattice quantum antiferromagnet

Direct Visualisation of Skyrmion Lattice Defect Alignment at Grain Boundaries

Magnetic and structural properties of Ni-substituted magnetoelectric Co4Nb2O9

Robustness of Basal-Plane Antiferromagnetic Order and the Jeff=1/2 State in Single-Layer Iridate Spin-Orbit Mott Insulators

Electric-Field-Induced Skyrmion Distortion and Giant Lattice Rotation in the Magnetoelectric Insulator Cu2OSeO3

Magnetic Excitations and Electronic Interactions in Sr2CuTeO6: A Spin-1/2 Square Lattice Heisenberg Antiferromagnet