Fabrication of superconductingMgB2 thin films on textured Cu(100) tape by hybrid physical–chemical vapor deposition

Abstract

We report on the fabrication of superconductingMgB2 thin films on textured Cu(100) tape under low pressure and temperature by using ahybrid physical–chemical vapor deposition (HPCVD) technique to explore thepossible broad range of deposition. Thermodynamic calculations for the Mg–Bsystem have been carried out and the pressure–temperature phase diagram wasobtained. Our results demonstrate that the deposition of superconductingMgB2 films is possible beyond the theoretically calculated growth window, where the sublimationof Mg is taking place. The structural and microstructural investigations reveal thatMgB2 filmsare c-axis-oriented normal to the substrate. The highestJc of∼1.34 × 105 A cm−2 at 5 K under 3 T is obtained for the film grown at460 °C. The critical currentdensity (Jc) and fluxpinning force density (Fp) of MgB2 films are enhanced with decreasing growth temperature. This could beattributed to the high density of grain boundaries which may act as effectiveflux pinning centers. These findings suggest an alternative route to fabricateMgB2 tapes at low temperature for large scale applications.