Artificial pinning centres in YBCO thin films induced by substrate decoration with gas-phase-prepared Y₂O₃nanoparticles

Y 2 O 3 nanoparticles prepared by an inert gas phase condensation process were used to introduce artificial pinning centres in YBa 2 Cu 3 O 7−δ thin films. The areal density of the particles was varied between 120 and 4200 particles µm −2 without changing the mean particle diameter of approximately 9 nm. Y 2 O 3 particles were deposited on TiO 2 terminated SrTiO 3 (100) single-crystal substrates with areal densities up to 1654 particles µm −2 and subsequently covered with YBa 2 Cu 3 O 7−δ by off-axis pulsed laser deposition (PLD). The areal density of the room temperature deposited particles is not changed by the substrate heating during PLD although their height on the substrate decreases. An influence on J c is demonstrated for particle densities above 1588 particles µm −2 , indicating that the substrate decoration with Y 2 O 3 nanoparticles from the gas phase affects the formation of artificial pinning centres in the YBa 2 Cu 3 O 7−δ films and can be applied to further study of the effect of particle size and areal density on defect formation in YBa 2 Cu 3 O 7−δ .