News

Assistant Professor Anton Gradišek, PhD from the Department of Condensed Matter Physics F5 and colleagues from the Department of Intelligent Systems E9 and University medical centre Ljubljana have published in Frontiers in Cardiovascular Medicine the article Identification of decompensation episodes in chronic heart failure patients based solely on heart sounds.

Chronic heart failure is a pressing health concern, affecting 2% of population worldwide and up to 10% of people above the age of 65. Decompensation episodes, when the patient feels particularly bad, result in hospitalizations, which are a burden both for patients and the health system. However, if an upcoming decompensation episode is detected early enough, hospitalization can be avoided by adjustment of treatment. In this study, we developed a machine-learning algorithm that distinguishes between decompensation and recompensation (when the patient feels well) episode based on heart sounds, recorded using a digital stethoscope. Our algorithm substantially outperforms the classification by cardiology experts and has potential for incorporation into a tele-monitoring system to help the patients.

Assistant Professor Anton Gradišek, PhD from the Department of Condensed Matter Physics F5 and colleagues from Australia have published in Sustainable Energy Fuels the article Hydrated lithium nido-boranes for solid–liquid hybrid batteries.

Hydridoborate salts are considered as promising solid-state electrolyte candidates for the development of solid-state batteries (SSBs). The presence of coordinated water in the crystal structure may facilitate the migration of the cation, yielding compounds with high ionic conductivity. In the present study, two samples of hydrated LiB11H14, here called LiB11H14·2H2O and a-LiB11H14·(H2O)n (n < 2), demonstrate remarkably different properties as solid-state electrolytes. Using a series of analytical methods, we studied these two materials as possible candidates for solid-liquid hybrid batteries.

From 1 to 2 December 2022, the Slovenian Research Agency organized the ARRS Day 2022: Supporting Excellence at the Grand Hotel Union in Ljubljana. This is a traditional event, which also included the awarding of the Excellence in Science 2022 prizes for the best research achievements in the previous year. Among the winners in the field of Natural Sciences and Engineering was Andrej Zorko, a member of the Condensed Matter Physics Department (F5). He made a public presentation of his group’s achievement entitled “Ising spin liquid”.

Dr Žiga Kos, a member of the Department of Condensed Matter Physics F5 at the Jožef Stefan Institute and Faculty of Mathematics and Physics at University of Ljubljana, received the Top research achievent award for his paper titled Nematic bits and universal logic gates. Žiga Kos showed in collaboration with Jörn Dunkel that topological defects in nematic fluids can be used as computational elements (nematic bits). Logic operations on nematic bits can be implemented using time-dependent electric fields. Nematoelastic interactions lead to strong correlations in systems of multiple nematic bits, which can be used to implement universal logic gates. The paper is an important step towards processing information in soft matter systems and has been highlighted in New Scientist and Physics World.

Professor Vid Bobnar, PhD from the Department of Condensed Matter Physics F5, researchers from the Advanced Materials Department K9, and researchers from France, Switzerland, the Netherlands and the Czech Republic have published in Applied Physics Letters the article Large imprint in epitaxial 0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 thin films for piezoelectric energy harvesting applications.

Pure and high crystalline quality 500 nm thick PMN–33PT films were grown by pulsed laser deposition on various SrRuO3 buffered substrates. Under compressive epitaxial strain, i.e. under small lattice mismatch between the substrate and PMN–33PT, high teragonality and ferroelectric P-E loops are stabilized. On the other hand, the strain is relaxed in PMN–33PT grown on a substrate with a larger lattice mismatch, and the film displays a relaxor-like hysteresis loop and enhanced piezoelectric response. Both the strained and relaxed SRO/PMN–33PT/Au capacitors exhibit a very large negative self-bias, which is induced by the alignment of defect dipoles with the polarization and is tuned by the epitaxial strain. This imprint permits the stabilization of a robust positive polarization state and low dielectric permittivity. The functional response of our films is in fact comparable to PZT-based thin films with the highest figure of merit, and demonstrates the possibility of developing piezoelectric devices based on high quality PMN–PT thin films.