Scientific Highlights
15th International Conference on Muon Spin Rotation
The 15th International Conference on Muon Spin Rotation, Relaxation and Resonance (µSR2020) will be held in Parma, Italy, from 6-10th July, 2020.
The conference is organized by the University of Parma in conjunction with eth ISIS Muon and Neutron Source.
Magnetism in semiconducting molybdenum dichalcogenides
Transition metal dichalcogenides (TMDs) are interesting for understanding the fundamental physics of two-dimensional (2D) materials as well as for applications to many emerging technologies, including spin electronics.
Time-Reversal Symmetry Breaking in Re-Based Superconductors
To trace the origin of time-reversal symmetry breaking (TRSB) in Re-based superconductors, we performed comparative muon-spin rotation and relaxation (μSR) studies of superconducting noncentro-symmetric Re0.82Nb0.18 (Tc=8.8 K) and centrosymmetric Re (Tc=2.7 K).
Anomalous Hall effect in Weyl semimetal half-Heusler compounds RPtBi (R = Gd and Nd)
GdPtBi and NdPtBi belong to the Heusler family of compounds and are conventional antiferromagnets below 9 and 2.1 K, respectively. We present evidence for magnetic-field–induced Weyl physics in these compounds, namely, a chiral anomaly (negative magnetoresistance) and an anomalous Hall effect (AHE) with a large anomalous Hall angle over a wide range of temperature. The AHE and chiral anomaly have a similar temperature dependence, indicating their common origin.
Collective magnetism in an artificial 2D XY spin system
Two-dimensional magnetic systems with continuous spin degrees of freedom exhibit a rich spectrum of thermal behaviour due to the strong competition between fluctuations and correlations. When such systems incorporate coupling via the anisotropic dipolar interaction, a discrete symmetry emerges, which can be spontaneously broken leading to a low-temperature ordered phase.
Isotope effect on the spin dynamics of single-molecule magnets probed by muon spin spectroscopy
Muon spin relaxation (μSR) experiments on a single molecule magnet enriched in different Dy isotopes detect unambiguously a slowing down of the zero field spin dynamics for the non-magnetic isotope. This occurs in the low temperature regime dominated by quantum tunnelling, in agreement with previous ac susceptibility investigations. In contrast to the latter, however, μSR is sensitive to all fluctuation modes affecting the lifetime of the spin levels.
Observation of Anomalous Meissner Screening in Cu/Nb and Cu/Nb/Co Thin Films
We have observed the spatial distribution of magnetic flux in Nb, Cu/Nb, and Cu/Nb/Co thin films using muon-spin rotation. In an isolated 50-nm-thick Nb film, we find a weak flux expulsion (Meissner effect) which becomes significantly enhanced when adding an adjacent 40 nm layer of Cu. The added Cu layer exhibits a Meissner effect (due to induced superconducting pairs) and is at least as effective as the Nb to expel flux.
Breakdown of Magnetic Order in the Pressurized Kitaev Iridate β-Li2IrO3
Temperature-pressure phase diagram of the Kitaev hyperhoneycomb iridate β-Li2IrO3 is explored using magnetization, thermal expansion, magnetostriction, and muon spin rotation measurements, as well as single-crystal x-ray diffraction under pressure and ab initio calculations.
Spin-liquid-like state in a spin-1/2 square-lattice antiferromagnet perovskite induced by d10 – d0 cation mixing
A quantum spin liquid state has long been predicted to arise in spin-1/2 Heisenberg square-lattice antiferromagnets at the boundary region between Néel (nearest-neighbor interaction dominates) and columnar (next-nearest-neighbor interaction dominates) antiferromagnetic order. However, there are no known compounds in this region. Here we use d10 – d0 cation mixing to tune the magnetic interactions on the square lattice while simultaneously introducing disorder.