Effect of O2 partial pressure on YBa2Cu3O7−δ thin film growth by pulsed laser deposition

Abstract

Abstract YBa 2 Cu 3 O 7− δ thin films were processed by pulsed laser deposition on (1 0 0) LaAlO 3 substrates using O 2 partial pressures from 120 to 1200 mTorr. The effect of O 2 pressure on film properties including room temperature resistivities and microstructures was studied for a unique set of deposition parameters. The film quality was observed to remain high over a wide range of O 2 partial pressures, with much less sensitivity to O 2 pressure than previous studies which are compared. For O 2 pressures from 200 to 1200 mTorr, superconducting transition temperatures consistently reached values >91.5 K and transport critical current densities were 3–5 MA/cm 2 (77 K, self-field). It is proposed that less sensitivity of film properties to O 2 pressure is achieved by: (1) reducing the particle velocity of the plume below a critical threshold, and (2) using a deposition temperature of 785 °C for adequate surface activation.