Abstract: Optimizing high-T_c superconducting materials for the production of controlled nanodevices is critical for industrial applications. In my presentation I will present the results of our group research showing the effect of a small amount of YMnO₃(YMO) multiferroic from 0.1 wt% to 5.0 wt% on the change of microstrultural and superconducting properties of the basic high-T_c YBa₂Cu₃O_7‒δ (YBCO) superconductor. The Raman spectra measurements showed a slight deterioration of the YBCO‒YMO superconducting state in the total YMO content, which is due to the disappearance of the orthorhombic phase seen as the O(4) band shifting towards higher wave numbers. It was found from magnetic measurements that a small addition of YMO (about 1.0 wt%) Does not significantly change the properties of the superconducting YBCO crystallites, and most composites show a critical temperature (T_c) close to 92 K.

The presentation will also discuss the results of the diffusion process between YBCO and Fe particles in the amount of 1.0 wt% to 25.0 wt%. Fe diffusion into YBCO arrays can be fundamental to multilayer systems with YBCO|Fe-stop interfaces. The test results (X-ray diffraction and Mössbauer spectroscopy) showed that the orthorhombic structure of YBCO assumes 3.0 wt%. Fe, while with a higher Fe content, the formation of BaFeO_3-δ and iron oxides was observed. The measurements also confirmed the strong suppression of superconductivity in YBCO-Fe materials containing more than 7 wt% Fe. Thanks to the XAS absorption edge research carried out at the "Solaris UJ" Synchrotron Center in Kraków, the valence of Cu²⁺ was confirmed, and a contribution of the 2p3d10L final states was evidenced, (where L - stands for ligand hole), which provides crucial information on the mobility of electrical carriers from the Cu–O₂ planes.

Keywords: High-T_c superconductors, Multiferroic and iron compositions, Ceramics materials, Diffusivity, Structure and magnetic properties, Spectroscopic measurements

Biography: Dr. Paweł Pęczkowski is an Assistant Professor in the Institute of Physical Sciences at the Faculty of Mathematics and Natural Sciences at the Cardinal Stefan Wyszyński University in Warsaw in Poland. He received his M.Sc. with honors and Ph.D. degrees in Physics from the Institute of Experimental Physics, Faculty of Physics, University of Warsaw. He obtained his Ph.D. in 2010. He is a member of the European and Polish Physical Society. His current research is concentrated on the synthesis and study of structural, superconducting and magnetic properties of low and high temperature unconventional superconductors, multiferroic-superconductor composites and heterostructures, foam superconducting, both in terms of basic research and their applications in electronics, as well as energy storage devices.