Smooth YBa2Cu3O7−<i>x</i> thin films prepared by pulsed laser deposition in O2/Ar atmosphere

Abstract

We report on pulsed laser deposition of YBa2Cu3O7−x in a diluted O2/Ar gas resulting in thin epitaxial films which are almost outgrowth-free. Films were deposited on SrTiO3 or MgO substrates around 800 °C at a total chamber pressure of 1.0 mbar, varying the argon partial pressure from 0 to 0.6 mbar. The density of boulders and outgrowths usual for laser deposited films varies strongly with Ar pressure: the outgrowth density is reduced from 1.4×107 to 4.5×105 cm−2 with increasing Ar partial pressure, maintaining a critical temperature Tc,zero≊90 K and a transport critical current density Jc(77 K)≥106 A/cm2 by extended oxygenation time during cool down.