News

Matej Pregelj from the Department of Condensed Matter Physics F-5, in collaboration with colleagues from the Department of Thin Films and Surfaces and other researchers from Slovenia and Serbia, published the article Perpendicular magnetic anisotropy at room-temperature in sputtered a-Si/Ni/a-Si layered structure with thick Ni (nickel) layers. In the article, they presented a detailed study of nanometer Si/Ni/Si layers, where perpendicular magnetic anisotropy was observed. It is one of the first observations of this property in Si/Ni/Si layers and thus opens up possibilities for the use of such layers in memory units, sensors, logic chips, etc.

Dr. Dejvid Črešnar, Nikita Derets, Dr. Andraž Rešetič, Dr. Marta Lavrič, Prof. Dr. Boštjan Zalar, prof. Dr. Samo Kralj, Prof. Dr. Zdravko Kutnjak, Assist. Prof. Dr. Brigita Rožič from the Department of Condensed Matter Physics F5, former colleague of the Department of Condensed Matter Physics F-5 Dr. Maja Trček, and colleagues Assist. Prof. Dr. Gregor Skačej, Faculty of Mathematics and Physics, University of Ljubljana, and Prof. Dr. Valentina Domenici, Department of Chemistry and Industrial Chemistry, University of Pisa, Italy, have, on the invitation (to Rožič) of Editors Prof. Dr. N. Mathur and Prof. Dr. X. Moya from the University of Cambridge, published an article entitled Caloric effects in liquid crystal-based soft materialsin a special issue of the Journal of Physics: Energy (IF=7.5) dedicated to caloric materials. In the mentioned article, the authors presented their latest research results of very large caloric responses observed in soft materials such as liquid crystals (TK) and liquid crystal elastomers (TKE). Through direct measurements, they showed that the size of the electrocaloric phenomenon in TK could exceed 8.3 K at a relatively small change in the electric field of 30 kV/cm and the existence of a record high elastocaloric responsivity of 24.2K/MPa in TKE.

Denis Arčon and Matej Pregelj from the Department of Condensed Matter Physics F5, in collaboration with colleagues from the University of Nova Gorica and researchers from Bulgaria, published the article The Role of Lattice Defects on the Optical Properties of TiO2 Nanotube Arrays for Synergistic Water Splitting. The article reports a one-step chemical method that enables the reduction of an array of titanium dioxide nanotubes with point defects. In-depth chemical analysis is supported by electron paramagnetic resonance measurements, which confirm the presence of oxygen vacancies. The prepared samples show an enhanced photocurrent for water splitting due to pronounced light absorption in the visible region, enhanced electrical conductivity, and improved charge transportation.

On June 2, 2023, the President of Slovenia, Nataša Pirc Musar, visited the Bio-Integrated Photonics Lab at the Jožef Stefan Institute. Matjaž Humar and Abdur Rehman Anwar presented her with some recent results under the project FoodTraNet. They conducted a live demonstration of the photonic barcodes. There was also a short debate about the importance of novel methods for tracking quality and authenticity of various foods.

Samo Kralj from the Department of Solid State Physics F5 and colleagues from Faculty of Mathematics and Physics, University of Ljubljana and Case Western Reserve University, Cleveland published an article in the journal Crystals with the title Reconfiguration of nematic disclinations in plane-parallel confinements.

They study numerically the reconfiguration process of colliding |m|=1/2 strength disclinations in a nematic liquid crystal (NLC). A Landau-de Gennes approach in terms of a tensor nematic order parameters is used. Initially, different pairs of parallel wedge disclinations were formed connecting opposite substrates confining the NLC in a plane-parallel cell. The collisions are triggered by the relative rotation of the azimuthal angle of the substrates that strongly pin the defect end points. They illustrate qualitatively different rewiring processes.