Superconducting HfO₂-added solution-derived YBa₂Cu₃O₇ nanocomposite films: the effect of colloidal nanocrystal shape and crystallinity on pinning mechanism

Abstract

Two different types of monoclinic HfO2 nanocrystals were employed in this work to study the effect of nanocrystal shape and crystallinity on the structural defects in the YBCO matrix as it lead to an enhancement of pinning performances of solution-derived YBCO nanocomposite films. In this work the nanorod-like HfO2 nanocrystals obtained from surfactant-controlled synthesis led to short intergrowths surrounding the particles while spherical HfO2 nanocrystals from the solvent-controlled synthesis led to the formation of long stacking faults in the YBCO matrix. It means that the small difference in crystallinity, lattice parameters, nanocrystal structures, core diameter of preformed nanocrystals in colloidal solutions give a strong influence on the formation of the structural defects around the particles in the YBCO matrix, leading to different pinning performances.

Focus on recent advances in superconducting films

“…The other three articles about REBCO films introduced artificial pinning centres focusing on different aspects. On the one hand, Rijckaert et al followed the CSD ex-situ approach for the preparation of nanocomposite films and studied the effect of shape and crystallinity of the pre-formed nanocrystals on the pinning mechanism [5]. Two distinct nanoparticle synthesis methods led to HfO 2 nanoparticles with different shape and crystallinity.…”