1. Electrocaloric and pyroelectric properties of ▫$0.6Ba_{0.85}Ca_{0.15}Zr_{0.10}Ti_{0.90}O_3$▫–▫$0.4BaTi_{0.89}Sn_{0.11}O_3$▫ ceramicsSoukaina Merselmiz, Zouhair Hanani, Hana Uršič Nemevšek, Uroš Prah, Daoud Mezzane, Matjaž Spreitzer, Brigita Rožič, Mimoun El Marssi, Zdravko Kutnjak, 2024, izvirni znanstveni članek Povzetek: Ferroelectric materials are gaining considerable attention for energy storage, electrocaloric and pyroelectric energy harvesting applications. In particular, Ba0.85Ca0.15Zr0.10Ti0.90O3 (BCZT) and BaTi0.89Sn0.11O3 (BTSn) ceramics are among the best-studied lead-free BaTiO3-based ferroelectrics with high piezoelectric and electrocaloric properties. In this work, we prepared a 0.6BCZT–0.4BTSn solid solution. The structural, energy storage, electrocaloric, and pyroelectric properties are investigated. An energy density of 61.4 mJ cm-3 with a high energy efficiency of 82.4 % at 90 °C is achieved. The electrocaloric temperature change, which is determined indirectly via the Maxwell relation, is 0.5 K at 86 °C and 25 kV cm-1. It is stable over a wide temperature range of around 65 °C and has a coefficient of performance of 15. Moreover, a pyroelectric energy density of 124.1 mJ cm-3 is achieved. The results of this study show that the 0.6BCZT–0.4BTSn ceramics is a multifunctional material with energy storage, electrocaloric and pyroelectric properties.
Ključne besede: electronic ceramics, lead-free ceramics, energy storage, energy harvesting, pyroelectric, electrocaloric
Objavljeno v DiRROS: 18.06.2026; Ogledov: 52; Prenosov: 55
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2. Microstructural engineering of sodium potassium niobate for enhanced and temperature-stable electromechanical responseAndraž Bradeško, Janina Roknić, Nejc Suban, Katarina Žiberna, Silvo Drnovšek, Brigita Kmet, Aadil Abass Shah, Marko Robić, Hana Uršič Nemevšek, Tadej Rojac, Andreja Benčan, Barbara Malič, 2026, izvirni znanstveni članek Povzetek: The development of high-performance lead-free piezoelectrics is a critical step toward sustainable electronic components, yet matching the electromechanical stability over external variables, such as temperature, of lead-based standards remains a significant challenge. This study investigates the synergistic effects of Ti-doping and K5.4Cu1.3Ta10O29 (KCT) co-modification on the structural and functional properties of (K0.5Na0.5)NbO3 (KNN) ceramics. Co-modification significantly enhances both electromechanical coupling and the mechanical quality factor, parameters essential for ultrasonic transducer applications. A comparative analysis of the ferroelectric behavior reveals that these modifications establish a stable internal bias field leading to the hardening of piezoelectric properties. Interestingly, the samples modified solely by Ti exhibit a stronger internal bias field than the Cu-containing co-modified samples, a phenomenon further explored through domain imaging. When benchmarked against commercial hard PZT, the optimized KNN-Ti-KCT ceramic demonstrates comparable thermal stability in the room-temperature to 100°C range. Although a trade-off exists between peak piezoelectric coefficients and environmental impact, these results highlight the potential of tailored KNN ceramics as reliable lead-free alternatives for high-temperature electromechanical devices.
Ključne besede: electronic ceramics, piezoelectricity, electromechanical stability
Objavljeno v DiRROS: 25.05.2026; Ogledov: 166; Prenosov: 140
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3. Impact of sintering temperature on structural, microstructural and electrical properties of screen-printed ▫$0.7Pb(Fe_{0.5}Nb_{0.5})O_3–0.3BiFeO_3$▫ thick filmsIvana Goričan, Andreja Benčan, Silvo Drnovšek, Antonio Iacomini, Nejc Suban, Brigita Kmet, Uroš Prah, Tadej Rojac, Hana Uršič Nemevšek, 2026, izvirni znanstveni članek Povzetek: (1–x)Pb(Fe0.5Nb0.5)O3–xBiFeO3 (PFN–100xBFO) ceramics exhibit versatile functional properties, from ferroelectric, relaxor to antiferroelectric behaviour, but have not yet been prepared as ceramic thick films, which are the key to miniaturization of electronic components. In this work, screen-printed thick films of PFN–30BFO were prepared on gold-coated alumina substrates and sintered at 800 °C, 850 °C and 930 °C. The impact of the sintering temperature on their properties was studied. The films annealed at 930 °C exhibited excessive electrical conductivity. In contrast, well developed polarization versus electric field hysteresis loops were observed in the films treated at 800 °C and 850 °C. The films annealed at 800 °C had the smallest grain size and dielectric permittivity values but achieved the highest dielectric breakdown strength. The findings of this study highlight the potential of PFN–30BFO screen-printed films, sintered at 800 °C, for use in miniaturized high-voltage electronic devices.
Ključne besede: thick films, electronic ceramics, sintering temperature
Objavljeno v DiRROS: 20.04.2026; Ogledov: 237; Prenosov: 146
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4. Capacitive energy-storage and electromechanical properties of aerosol-deposited ▫$0.5BaZr_{0.2}Ti_{0.8}O_3–0.5Ba_{0.7}Ca_{0.3}TiO_3$▫ filmsSoukaina Merselmiz, Ivana Goričan, Tadej Rojac, Vid Bobnar, Victor Regis de Moraes, Matej Šadl, Val Fišinger, Nejc Suban, Brigita Kmet, Andreja Benčan, Andraž Bradeško, Andrej Debevec, Barbara Malič, Hana Uršič Nemevšek, 2026, izvirni znanstveni članek Ključne besede: electronic ceramics, powder aerosol composition, thin films, ferroelectricity, energy storage, electromechanical properties
Objavljeno v DiRROS: 08.12.2025; Ogledov: 950; Prenosov: 333
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5. The role of carbon presence on the strontium hexaferrite phase decomposition during pressureless spark plasma sintering (pSPS)Aleksander Učakar, Andraž Kocjan, Blaž Belec, Janez Košir, Tanja Kallio, Marjeta Maček, Bor Arah, Petra Jenuš, 2025, izvirni znanstveni članek Povzetek: The phase composition and microstructure of Sr-hexaferrite (SFO) ceramics govern the hard magnetic properties. Here, pressureless spark plasma sintering (pSPS) technique was employed for the rapid consolidation (500°C/min) of SFO in a radiating graphite crucible under vacuum and, thus, reductive conditions. A numerical model depicting the temperature profile within the heating crucible was constructed to understand the temperature evolution within the samples. The combination pSPS sintering environment (graphite heating crucible under vacuum) promoted phase decomposition to Sr-enriched and depleted phases of various morphological variations, leading to reduction of hard magnetic properties. Notably, certain newly formed phases exhibited lower melting points, inducing a shift in the sintering mechanism from solid-state sintering to a partial liquid-phase sintering mechanism.
Ključne besede: pressureless spark plasma sintering, electronic ceramics, numerical simulations
Objavljeno v DiRROS: 03.09.2025; Ogledov: 805; Prenosov: 795
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6. Unlocking high capacitive energy-density in Sm-doped ▫$Pb(Mg_{1/3}Nb_{2/3})O_3–PbTiO_3$▫ thin films via strain and domain engineeringZouhair Hanani, Jamal Belhadi, Nina Daneu, Urška Trstenjak, Nick A. Shepelin, Vid Bobnar, Thomas Lippert, Matjaž Spreitzer, 2025, izvirni znanstveni članek Ključne besede: relaxor ferroelectrics, thin films, strain analysis, electronic ceramics
Objavljeno v DiRROS: 17.04.2025; Ogledov: 1185; Prenosov: 548
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