Upper critical fields up to 60 T in dirty magnesium diboride thin films

C. Ferdeghini, V. Ferrando, C. Tarantini, E. Bellingeri, G. Grasso, A. Malagoli, D. Marrè, M. Putti, P. Manfrinetti, A. Pogrebnyakov, J. M. Redwing, X. X. Xi, R. Felici, E. Haanappel

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Abstract

Upper critical fields of several magnesium diboride thin films were measured up to 28 T at the Grenoble High Magnetic Field Laboratory (GHMFL) in Grenoble and up to 60 T at the Laboratoire National des Champs Magnétiques Pulsés (LNCMP) in Toulouse. The samples were prepared both by pulsed laser deposition (PLD) and hybrid physical chemical vapor deposition (HPCVD) technique; they have critical temperatures between 29 and 39 K and normal state resistivities between 5 and 250 μΩ cm; one of them has been intentionally doped with carbon. The measured critical fields, μ0 Hc2, were exceptionally high; we obtained the record value of 52 T at 4.2 K in the parallel orientation. In contrast with the BCS predictions, no saturation in Hc2 at low temperature was observed. Furthermore, films with a wide range of resistivity values showed similar critical fields, suggesting that in a two band system resistivity and H c2 are not trivially linked. The high Hc2 values seem to be related with the expanded c-axis. The structure of one of the samples was carefully investigated with X-ray diffraction at European Synchrotron Radiation Facility (ESRF) in Grenoble.

Original languageEnglish (US)
Pages (from-to)3234-3237
Number of pages4
JournalIEEE Transactions on Applied Superconductivity
Volume15
Issue number2 PART III
DOIs
StatePublished - Jun 1 2005

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

Cite this

Ferdeghini, C., Ferrando, V., Tarantini, C., Bellingeri, E., Grasso, G., Malagoli, A., Marrè, D., Putti, M., Manfrinetti, P., Pogrebnyakov, A., Redwing, J. M., Xi, X. X., Felici, R., & Haanappel, E. (2005). Upper critical fields up to 60 T in dirty magnesium diboride thin films. IEEE Transactions on Applied Superconductivity, 15(2 PART III), 3234-3237. https://doi.org/10.1109/TASC.2005.848827