Jc enhancement in YBa2Cu3Ox thin films by introduction of one-dimensional artificial pinning centers

A novel technology to introduce artificial pinning centers (APCs) into YBa2Cu3O7-delta (YBCO) thin films prepared by pulsed laser deposition (PLD) was investigated for a drastic improvement of J(c) in the films. Linear-like defects (one-dimensional APCs) were introduced perpendicular to the surface of the c-axis oriented films during the deposition process by using distributed Y2O3 nano-islands on substrates. The density of nano-islands was varied within 0.8 - 1.2 x 10(10)/cm(2) by PLD. A normalized resistivity as a function of temperature in magnetic fields shows a sharper resistivity drop for the film with APC, compared to pure YBCO film. J(c) of the film with APC was also increased to 0.12 MA/cm(2) (77 K, B//c, 5 T), which was about two times higher than that of the pure YBCO film. The film had a very large Jc peak when the field was applied close to the c-axis. The peak J(c) increased with the number density of Y2O3 nano-islands. This indicates that strong APCs parallel to the c-axis were incorporated into the YBCO film.