Superconducting thin films of MgB 2 on Si by pulsed laser deposition

Abstract

Superconducting thin films have been prepared on Si-substrates, using pulsed laser deposition from a target composed of a mixture of Mg and MgB 2 powders. The films were deposited at room temperature and annealed at 600°C. The zero resistance transition temperatures were 11–15.5 K, with an onset transition temperature of 27 K. Special care has been taken to avoid oxidation of Mg in the laser plasma and deposited film, by optimizing the background pressure of Ar gas in the deposition chamber. For this the optical emission in the visible range from the plasma has been used as indicator. Preventing Mg from oxidation was found to be essential to obtain superconducting films.