Single-Crystal like MgB2 thin films grown on c-cut sapphire substrates

Single-crystal like MgB2 thin film was grown on (000l) Al2O3 substrate by using hybrid physical-chemical vapor deposition (HPCVD) system. Single crystal properties were studied by X-ray diffraction (XRD) and the full width at half maximum (FWHM) of the (0001) MgB2 peak is 0.15 degrees, which is very close to that has been reported for MgB2 single-crystal. It indicates that the crystalline quality of thin film is good. Temperature dependence on resistivity was investigated by physical property measurement system (PPMS) in various applied fields from 0 to 9 T. The upper critical field (H-c2) and irreversibility field (H-irr) were determined from PPMS data, and the estimated values are comparable with that of MgB2 single-crystals. The thin film shows a high critical temperature (T-c) of 40.4 K with a sharp superconducting transition width of 0.2 K, and a high residual resistivity ratio (RRR=21), it reflects that MgB2 thin film has a pure phase structure.