INNOVATIVE APPROACHES FOR CONTROL OF MULTIFERROIC FUNCTIONAL RESPONSES

Innovative approaches for control of multiferroic functional responses

Caloric materials are intensively studied for use in new environmental-friendly solid-state cooling systems. In the frame of the project J2-9253 Multicaloric cooling, the Electronic Ceramics Department research group develop single-phase multicaloric materials that combine electrocaloric and magnetocaloric effects. The materials are based on lead iron niobate and bismuth ferrite and exhibit extremely high temperature differences of 2 to 2.5 K for each individual effect. To achieve high caloric effects, the materials should exhibit low electrical conductivity. The researchers from the Electronic Ceramics, Solid State Physics and Nanostructured Materials departments at Jožef Stefan Institute, the researchers from Institute of Chemistry in Ljubljana and colleagues from America and Poland, have developed innovative approaches to control electrical conductivity in the multiferroics. These approaches are based on the control of chemical compositions and heat treatments during material processing. The research achievements, which were mainly carried out in Slovenia, are published in high-impact international journals, including Nature Communications.

The figure shows the local properties of bismuth ferrite ceramics determined by an atomic force microscope: (a) piezoelectric response, (b) electrical conductivity of domain walls (DW), and (c) line profile of electrical conductivity measured in the area marked by the blue line in Figures (a) and (b). The red arrows in Figure (b) mark conductive DWs [after Benčan et al., Nat. Commun. 2020].

References:

Ø BENČAN, Andreja, DRAŽIĆ, Goran, URŠIČ NEMEVŠEK, Hana, MAKAROVIČ, Maja, KOMELJ, Matej, ROJAC, Tadej. Domain-wall pinning and defect ordering in BiFeO₃ probed on the atomic and nanoscale. Nature communications, ISSN 2041-1723, 2020, vol. 11, pp. 1762-1-1762-8. Hyperlink: https://www.nature.com/articles/s41467-020-15595-0

Ø PRAH, Uroš, DRAGOMIR, Mirela, ROJAC, Tadej, BENČAN, Andreja, BROUGHTON, Rachel, CHUNG, Ching-Chang, JONES, Jacob L., SHERBONDY, Rachel, BRENNECKA, Geoff, URŠIČ NEMEVŠEK, Hana. Strengthened relaxor behavior in (1−x)Pb(Fe_0.5Nb_0.5)O₃-xBiFeO₃, Journal of materials chemistry. C, ISSN 2050-7526, 2020, vol. 8, no. 10, pp. 3452-3462. Hyperlink: https://pubs.rsc.org/en/content/articlelanding/2020/tc/c9tc05883d#!divAbstract

Ø PRAH, Uroš, WENCKA, Magdalena, ROJAC, Tadej, BENČAN, Andreja, URŠIČ NEMEVŠEK, Hana. Pb(Fe_0.5Nb_0.5)O₃−BiFeO₃- based multicalorics with room-temperature ferroic anomalies. Journal of materials chemistry. C, ISSN 2050-7534, 2020, vol. 8, no. 32, pp. 1282-11291. Hyperlink: https://pubs.rsc.org/en/content/articlelanding/2020/tc/d0tc02329a#!divAbstract

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