Preparation and properties of MgB2 thin films on LaAlO3 substrates by chemical vapour deposition

摘要

Superconducting MgB2 thin films have been prepared on single crystal LaAlO3 (001) substrates by an improved chemical vapour deposition technique. First, boron precursor films were grown on LaAlO3 (001) substrates by chemical vapour deposition using B2H6 as a boron source. Magnesium was then incorporated into the films during a post-annealing process in the presence of high purity magnesium bulk at 890 degreesC for 40 min. The resultant MgB2 films on LaAlO3 substrates showed a random orientation with dense and well-formed grains in the films. Resistance and do magnetization measurements of the films revealed a sharp superconducting zero resistance transition temperature of 37.5 K, while magnetization hysteresis measurements yielded critical current density J(c) of 2.6 x 10(7) A cm(-2) at 15 K in zero field. [References: 14]