Microstructure, pinning properties, and aging of CSD-grown SmBa$_2$Cu$_3$O$_{7−δ}$ films with and without BaHfO$_3$ nanoparticles

In order to improve the electrical transport properties of REBa$_2$Cu$_3$O$_7−δ$ nanocomposite films, SmBa$_2$Cu$_3$O$_{7−δ}$ films with and without BaHfO$_3$ nanoparticles were grown by chemical solution deposition, and their microstructural and transport properties were investigated in a detailed study using transmission electron microscopy and transport measurements in magnetic fields up to 24 T. The optimization process of the crystallization step (temperature and oxygen partial pressure) as well as an aging effect, which is due to the release of trapped fluorine, are described. Critical temperature and critical current densities surprisingly improve initially during the aging. Due to the complex microstructure, the additional BaHfO3 nanoparticles have only a positive effect at low magnetic fields for our samples.