Superconductivity and appearance of negative magnetocaloric effect in Ba1-xKxBiO3 perovskites, doped by Y, La and Pr

Recently, substantial attention is given to the bismuth-based perovskites for variety of electronic applications. The perovskites are used for quantum dots displays (QLED), photovoltaic systems and superconducting (HTS) devices. In this paper comprehensive studies of Ba(1-x)K(x)Bi(1-y)REyO(3) bismuth perovskites (REBKBO, RE = Y , La or Pr) are reported. Apart from structural anomalous behavior at low temperatures, the electronic properties of the REBKBO can be easily tailored by doping. For instance, critical current densities differ by 3 orders of magnitude from 0.07 kA/cm(2) (LaBKBO) to 65 kA/cm(2) (BKBO). To explain the above behavior, microstructural, magnetic, calorimetric, spectroscopic (FT-IR) studies and ab-initio electronic structure calculations were carried out. The FT-IR shows that the biggest difference in the spectrum compared to the undoped sample was recorded for PrBKBO, due to magnetic contribution of the Pr3+ multiplet. Electronic structure calculations revealed that the BKBO compound shows the highest DOS(E-F) compared to the other samples, however, the electronic structure of PrBKBO is very different. The negative magnetocaloric effect observed below 30 K is a highlight of the peculiar properties of that sample. These findings extend possible usage of bismuth-based perovskites towards new applications. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

This paper reports comprehensive studies of the electronic properties of Ba(1-x)K(x)Bi(1-y)REyO(3) bismuth perovskites (REBKBO, RE = Y , La or Pr), showing that these materials can have their electronic properties tailored by doping, with significant differences observed in the spectrum of PrBKBO due to the magnetic contribution of Pr3+ multiplet. A negative magnetocaloric effect was observed below 30 K, highlighting the peculiar properties of these materials.