Effects of BaZrO3 dispersion into EuBa2Cu3O7−δ superconducting thin films

Abstract

Surface resistances (RS) have been measured for EuBa2Cu3O7−δ (EuBCO) films grown in an ozone atmosphere. We grew BaZrO3 dispersed EuBCO films with artificial pinning centers (APCs) in an ozone atmosphere. We have investigated the effects of BaZrO3 dispersion into EuBCO films. The EuBCO films were grown using a pulsed laser deposition (PLD) in an ozone atmosphere on (100) SrTiO3 substrates. We use a pure EuBCO target and an EuBCO+1.0wt% BaZrO3 target. By BaZrO3 dispersion into EuBCO films, the crystallinity of BaZrO3 dispersed EuBCO films was poorer than that of pure EuBCO films. BaZrO3 dispersion into EuBCO films did not improve their superconducting characteristics. Then we evaluated microstructure by using transmission electron microscopy (TEM). We observed nano-rods in BaZrO3 dispersed EuBCO films. However, we did not observe nano-rods in BaZrO3 dispersed EuBCO films grown in an oxygen atmosphere. The differences between an ozone and an oxygen atmosphere influence on nano-rod forming. We found that the nano-rod size is important and is strongly related to not only RE (RE: Rare Earth) ion radii but also growth conditions of films.