Preparation of MgB2 superconducting thin films by magnetron sputtering

Superconductor MgB2 thin films with thickness 200 nm were prepared on sapphire substrates by co-deposition of boron and magnesium. Precursor MgB thin films were deposited from two independent magnetron sources—boron by rf magnetron sputtering and magnesium by dc magnetron sputtering. MgB precursor thin films annealed ex situ in argon atmosphere at temperature range from 500 °C to 700 °C exhibit smooth superconducting transition with onset critical temperature Tcon ⩽ 35 K and zero resistance Tc0 ⩽ 32  K. Preparation of microstructures and measurement of critical current density are also discussed.