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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.

During November 21–24, 2022, the international conference “European C-MetAC Days 2022” took place in Split, Croatia. The conference is organized annually by the European Integrated Center for the Development of New Metallic Alloys and Compounds, a legal successor of the European network of Excellence »Complex Metallic Alloys – CMA« from the 7th EU Framework program. A member of the European C-MetAC is also the Condensed Matter Physics Department of the Jožef Stefan Institute. The conference topics were the development and physical properties of new generations of metallic alloys. The first day of the conference was dedicated to honour scientific achievements of prof. Janez Dolinšek, at the occasion of his 65th birthday anniversary by a workshop “High-Entropy Alloys: From basic studies to industrial applications”. There, the lecturers have presented scientific achievements of Prof. Dolinšek in the fields of quasicrystals, complex metallic alloys and high-entropy alloys and emphasized his long-term cooperation with the members and groups incorporated in the European C-MetAC. After the workshop, the international colleagues and peers have arranged a short celebration entertainment.