High-field properties of carbon-doped MgB2 thin films by hybrid physical-chemical vapor deposition using different carbon sources

Wenqing Dai, V. Ferrando, A. V. Pogrebnyakov, R. H.T. Wilke, Ke Chen, Xiaojun Weng, Joan Redwing, Chung Wung Bark, Chang Beom Eom, Ye Zhu, P. M. Voyles, Dwight Rickel, J. B. Betts, C. H. Mielke, A. Gurevich, D. C. Larbalestier, Qi Li, X. X. Xi

Research output: Journal article publicationJournal articleAcademic researchpeer-review

17 Citations (Scopus)

Abstract

We have studied the high-field properties of carbon-doped MgB2 thin films prepared by hybrid physical-chemical vapor deposition (HPCVD). Carbon doping was accomplished by adding carbon-containing gas, such as bis(methylcyclopentadienyl)magnesium and trimethylboron, into the hydrogen carrier gas during the deposition. In both cases, Tc drops slowly and residual resistivity increases considerably with carbon doping. Both the a and c lattice constants increase with carbon content in the films, a behavior different from that of bulk carbon-doped MgB2 samples. The films heavily doped with trimethylboron show very high parallel Hc2 over 70T at low temperatures and a large temperature derivative near Tc. These behaviors are found to depend on the unique microstructure of the films, which consists of MgB2 layers a few-nanometers thick separated by non-superconducting MgB2C2 layers. This leads to an increase in the parallel Hc2 by the geometrical effect, which is in addition to the significant enhancement of Hc2 due to changes in the scattering rates within and between the two bands present in films doped using both carbon sources. The high Hc2 and high-field Jc(H) values observed in this work are very promising for the application of MgB 2 in high magnetic fields.
Original languageEnglish
Article number125014
JournalSuperconductor Science and Technology
Volume24
Issue number12
DOIs
Publication statusPublished - 1 Dec 2011
Externally publishedYes

ASJC Scopus subject areas

  • Ceramics and Composites
  • Condensed Matter Physics
  • Metals and Alloys
  • Materials Chemistry
  • Electrical and Electronic Engineering

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