Great progress has been made in the deposition of
MgB2
thin films since the discovery of superconductivity at 39 K in this
two-band superconductor. In this review, deposition techniques used for
MgB2
are described, with an emphasis on their meeting the critical requirements for growing high-quality
MgB2
thin films. The availability of these thin films has contributed
significantly to the research on the two-gap superconductivity in
MgB2.
MgB2
thin films have also been investigated for applications in high-field magnets,
superconducting electronic devices and circuits, and radio-frequency cavities used in
accelerators.