NUM division - Publication Highlights

Magnetic skyrmions, with their distinctive vortex-like magnetic spin configurations, continue to intrigue researchers due to their potential applications in nanoscience and technology. Traditionally skyrmions form two-dimensional hexagonal close-packed lattices, with the skyrmions themselves displaying one of just two types of internal magnetization texture known as Bloch- or Néel-type. Recent theories hinted at the prospect of reconfigurable transitions between skyrmion phases of different lattice types and internal textures. Until now, experimental evidence supporting such theories has been scarce.

We report on measurements of the in-plane magnetic penetration depth (λab) in single crystals of Sr₂RuO₄ down to ≃0.015  K by means of muon-spin rotation-relaxation. The linear temperature dependence of λ⁻²_ab for T≲0.7  K suggests the presence of nodes in the superconducting gap. This statement is further substantiated by observation of the Volovik effect, i.e., the reduction of λ⁻²_ab as a function of the applied magnetic field. The experimental zero-field ...

Kondo impurities provide a nontrivial probe to unravel the character of the excitations of a quantum spin liquid. In the S = 1/2 Kitaev model on the honeycomb lattice, Kondo impurities embedded in the spin-liquid host can be screened by itinerant Majorana fermions via gauge-flux binding. Here, we report experimental signatures of metallic-like Kondo screening at intermediate temperatures in the Kitaev honeycomb material α-RuCl₃ with dilute Cr³⁺ (S = 3/2) impurities.

Co oxides with perovskite-related structure are particularly promising, cost-effective OER catalysts. However, the increasing Co demand by the battery industry is pushing the search for Co-free alternatives. Here we investigate the potential of the Co-free layered perovskite family RBaCuFeO_5+δ (R = 4f lanthanide), where we identify the critical structural and electronic variables leading to high OER catalytical performance. The employed methodology, based in the use of advanced neutron and X-ray synchrotron techniques combined with ab initio DFT calculations allowed to reveal LaBaCuFeO_5+δ as new, promising Co-free electroctalyst. Moreover, we could show that this material can be industrially produced in nanocrystalline form. We believe that the reported results and methodology may contribute to the implementation of new technologies aimed to generate energy with lower carbon emissions, and can also inspire the scientific community in their search of other Co-free materials with good OER electrocatalytical properties.

RNA-binding proteins (RBPs) are crucial regulators of gene expression, often composed of defined domains interspersed with flexible, intrinsically disordered regions. Determining the structure of ribonucleoprotein (RNP) complexes involving such RBPs necessitates integrative structural modeling due to their lack of a single stable state. In this study, we integrate magnetic resonance, mass spectrometry, and small-angle scattering data to determine the solution structure of ...

Two-dimensional arrays of magnetically coupled nanomagnets provide a mesoscopic platform for exploring collective phenomena as well as realizing a broad range of spintronic devices. In particular, the magnetic coupling plays a critical role in determining the nature of the cooperative behavior and providing new functionalities in nanomagnet-based devices. Here, we create coupled Ising-like nanomagnets ...

The interplay between spin-orbit interaction and magnetic order is one of the most active research fields in condensed matter physics and drives the search for materials with novel, and tunable, magnetic and spin properties. Here we report on a variety of unique and unexpected observations in thin multiferroic Ge_1−xMn_xTe films.

Magnon polarons are novel elementary excitations possessing hybrid magnonic and phononic signatures, and are responsible for many exotic spintronic and magnonic phenomena. Despite long-term sustained experimental efforts in chasing for magnon polarons, direct spectroscopic evidence of their existence is hardly observed. Here, we report the direct observation of magnon polarons using neutron spectroscopy on a multiferroic Fe₂Mo₃O₈ possessing strong magnon-phonon coupling.