arXiv subjects

Uroš Cvelbar

Publications and source records attributed to Uroš Cvelbar.

3 recordsLinked to original sources

arXiv2026

Epitaxial Ni/Cu Superlattice Nanowires with Atomically Sharp Interfaces for Spin Transport

The importance of microstructure increases when decreasing the size of an object to the nanoscale, along with the complexity of controlling it. For instance, it is particularly complicated to create nano-object with controlled interfaces. Therefore, progressing towards 1D epitaxial nanostructures poses a challenge, and realization of their full potential is linked to technological issues of achieving large-scale, precise atom stacking of two or more different chemical elements. Achieving such coherent, epitaxial interfaces is a key step toward enabling spintronic phenomena in 1D objects, by minimizing interface scattering and strain-driven defects. Our results demonstrate a successful realization of controlled nanoscale heteroepitaxy in one-dimensional single-crystal structures. We fabricated nanowires composed of alternating magnetic (nickel) and non-magnetic, highly conductive (copper) segments. This periodic stacking modulates electron transport under magnetic stimuli. The epitaxial precision achieved eliminates detrimental electron scattering that has historically limited the magnetotransport properties of such 1D structures and hindered their development. Such materials are crucial for further advancements in the miniaturisation of nanosensors, actuators, and next-generation 3D spintronic devices.

cond-mat.mtrl-sci↗

arXiv2025

Order-disorder duality of high entropy alloys extends non-linear optics

Order versus disorder in the structure of materials plays a key role in the theoretical prediction of their properties. However, this structural description appears to be ineffective for new families of materials such as high entropy alloys (HEAs), which combine crystallographic order with chemical disorder. Here, we demonstrate for five-element HEAs as pure solid solutions that the chemical disorder of the elements decorating their cubic structure underlies the generation of second optical harmonics, overcoming the theoretical limit imposed on centrosymmetric crystals. Moreover, we discover that this disorder, inherent to HEAs, sets a threshold for non-linear light emission from the 4th to the 26th order. As a consequence of the 0.5 eV broadening of the energy levels of the five elements of the HEA, the emission spectrum covers broad visible (400-650 nm) and infrared (800-1600 nm) ranges. In addition to the challenge of theoretically predicting non-linear effects in unconventional materials, the duality of structural order and chemical disorder in HEAs offers the opportunity to design sustainable alternatives to urgently needed optical materials.

cond-mat.mtrl-sci↗

arXiv2025

The hidden sustainability bottleneck in high-entropy alloy design

Because of the enormous number of possible compositions, comparable to the number of stars in the universe, high-entropy alloys (HEAs) constitute a virtually inexhaustible materials space with highly versatile properties. Among these systems, HEAs are often proposed as potential substitutes for critical elements such as rare earths or platinum group metals. However, random or incremental exploration strategies are neither practical nor efficient at this scale. Targeted materials selection guided by sustainability considerations is therefore essential, yet identifying sustainable HEA compositions remains highly challenging. Here, we perform a comprehensive sustainability assessment of 30,201 equimolar HEA compositions and identify a resilient shortlist (approximately 5\%) that consistently exhibits favorable sustainability profiles across multiple evaluation schemes. Our analysis integrates complementary criteria including carbon footprint, environmental, social and governance (ESG) risks, production compatibility, and resource availability. The resulting sustainability-based ranking provides a strategic roadmap for HEA research, enabling experimental efforts to be focused on compositions that are not only functionally promising but also scalable and resource-responsible. By aligning materials discovery with sustainability and supply constraints, this framework supports more efficient use of experimental resources while contributing to long-term industrial sustainability goals.

physics.soc-ph↗