Ambient temperature epitaxial growth of MgB2 thin films with a Mg buffer layer

Abstract

We grew crystalline MgB2 thin films using molecular beam epitaxy at a low substrate temperature of 110 °C under an ultrahigh vacuum of about 10−6 Pa. MgB2 thin films were deposited on the (001) surface of a 4H-SiC substrate with an epitaxial Mg buffer layer. Superior crystallinity and surface flatness were confirmed by in situ reflection high-energy electron diffraction and X-ray diffraction measurements. The growth temperature was lower than any in prior reports on superconducting MgB2 thin films. Moreover, we successfully confirmed the occurrence of a sharp superconducting transition at 27.2 K.