NUM division - Publication Highlights

Co-based catalysts are promising candidates to replace Ir/Ru-based oxides for oxygen evolution reaction (OER) catalysis in an acidic environment. However, both the reaction mechanism and the active species under acidic conditions remain unclear. In this study, by combining surface-sensitive soft X-ray absorption spectroscopy characterization with electrochemical analysis, we discover that the acidic OER activity of Co-based catalysts are determined by their surface oxidation/spin state. 

LiCu₃O₃ is an antiferromagnetic mixed valence cuprate where trilayers of edge-sharing Cu(II)O (3d⁹) are sandwiched in between planes of Cu(I) (3d¹⁰) ions, with Li stochastically substituting Cu(II). Angle-resolved photoemission spectroscopy (ARPES) and density functional theory reveal two insulating electronic subsystems that are segregated in spite of sharing common oxygen atoms: a Cu d_z²/O p_z derived valence band (VB) dispersing on the Cu(I) plane, and a Cu 3d_x²−y²/O 2p_x,y derived Zhang-Rice singlet (ZRS) band dispersing on the Cu(II)O planes.

We present high-quality angle-resolved photoemission (ARPES) and density functional theory calculations (DFT+U) of SmCoIn₅. We find broad agreement with previously published studies of LaCoIn₅ and CeCoIn₅, confirming that the Sm 4f electrons are mostly localized. Nevertheless, our model is consistent with an additional delocalized Sm component, stemming from hybridization between the 4f electrons and the metallic bands at “hot spot” positions in the Brillouin zone. 

Alex Amato and Elvezio Morenzoni (both NUM) have published a new textbook entitled 'Introduction to Muon Spin Spectroscopy: Applications to Solid State and Material Sciences'. The book is ideal for a first course in muon spin spectroscopy (µSR), comes enriched with exercises and solutions to master the subject and includes practical examples to quantify key experimental parameters.

The study presents a unique investigation of [Pt/CoFeB/Ru]₁₀ multilayers, revealing suppressed skyrmion phases, intricate magnetic domain structures, and Néel-type domain walls, providing crucial insights for spintronic applications.

Charge density wave (CDW) orders in vanadium-based kagome metals have recently received tremendous attention, yet their origin remains a topic of debate. The discovery of ScV₆Sn₆, a bilayer kagome metal featuring an intriguing √3 × √3 × √3 CDW order, offers a novel platform to explore the underlying mechanism behind the unconventional CDW. Here we combine ...