Analytical electron microscopy study of the composition of BaHfO$_3$; nanoparticles in REBCO films: the influence of rare-earth ionic radii and REBCO composition

The critical current density of superconducting rare-earth barium copper oxide (REBCO) thin films is enhanced by adding nanoparticles to generate artificial pinning centers. Barium-based perovskites are popular nanoparticle materials. Although typically considered chemically unreactive in the surrounding REBCO matrix, previous studies have shown experimental evidence for rare-earth element (REE) incorporation from REBCO into the nanoparticles. However, not much is currently known about this chemical interaction.