High Upper Critical Field and Critical Current Density of Carbon-doped MgB$_{2}$ Films by HPCVD Using TMB

ORAL

Abstract

Carbon-doping is effective to enhance upper critical field $H_{c2}$ and critical current density $J_{c}$ of MgB$_{2}$. Using Trimethylboron (TMB) as the doping source, we have successfully fabricated carbon-doped MgB$_{2}$ thin films by the Hybrid Physical-Chemical Vapor Deposition (HPCVD) method. Large temperature derivative $-dH_{c2}^{//ab} /dT$ values near $T_{c}$, as high as 8.3 T/K, have been achieved for heavily doped samples. These values are much higher than what have been reported before. With $T_{c}$ over 30 K, $H_{c2}^{//ab} (0)$ values over 100 T can be expected for these samples. For lightly doped films, $J_{c}$ values, larger than 10$^{5}$ A/cm$^{2}$ at 5 K under 9 T perpendicular field and 10$^{4}$ A/cm$^{2}$ at 20 K under 5 T perpendicular field, were obtained. The results demonstrate that carbon-doped MgB$_{2}$ films by HPCVD using TMB are promising for high field applications.

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Authors

  • Wenqing Dai

    Department of Physics, Pennsylvania State University, University Park, PA 16802

  • Ke Chen

    Pennsylvania State University, Department of Physics, Pennsylvania State University, University Park, PA 16802, Deparment of Physics, Penn State University, University Park, PA 16802

  • Qi Li

    Pennsylvania State University, Department of Physics, Pennsylvania State University, University Park, PA 16802, Deparment of Physics, Penn State University, University Park, PA 16802

  • X.X. Xi

    Pennsylvania State University, Department of Physics, Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802, The Pennsylvania State University, Department of Physics and Department of Materials Science and Engineering, Penn State University, University Park, PA 16802