A novel technique for synthesizing MgB2 thin films with high upper critical fields

Y. Shen; R. Gandikota; Rakesh Singh; F. L. Hunte; J. Jaroszynski; D. C. Larbalestier; J. M. Rowell; Nathan Newman

doi:10.1088/0953-2048/21/8/085009

A novel technique for synthesizing MgB₂ thin films with high upper critical fields

Y. Shen, R. Gandikota, Rakesh Singh, F. L. Hunte, J. Jaroszynski, D. C. Larbalestier, J. M. Rowell, Nathan Newman

Research output: Contribution to journal › Article › peer-review

9 Scopus citations

Abstract

We report a new method for synthesizing magnesium diboride (MgB ₂) thin films which exhibit a steep increase in the slope of the upper critical field H_c2 versus decreasing temperature (i.e. |dH _c2/dT|_Tc|≈2.5 T K^-1). An H_c2 of 38.4 T at 4.2 K and an extrapolated value of H_c2(0) above 43 T at 0 K are reported. Films of magnesium plus boron were deposited on unheated c-plane sapphire substrates by co-evaporation, and were subsequently annealed in a reducing atmosphere at temperatures below 600 °C. The use of a combination of a magnesium-rich stoichiometry (Mg/B>1/2) for the as-deposited film and a two-step annealing process was found to be critical in obtaining these high values of H_c2 and |dH_c2/dT|_Tc|.

Original language	English (US)
Article number	085009
Journal	Superconductor Science and Technology
Volume	21
Issue number	8
DOIs	https://doi.org/10.1088/0953-2048/21/8/085009
State	Published - Aug 1 2008

ASJC Scopus subject areas

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

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10.1088/0953-2048/21/8/085009

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title = "A novel technique for synthesizing MgB2 thin films with high upper critical fields",

abstract = "We report a new method for synthesizing magnesium diboride (MgB 2) thin films which exhibit a steep increase in the slope of the upper critical field Hc2 versus decreasing temperature (i.e. |dH c2/dT|Tc|≈2.5 T K-1). An Hc2 of 38.4 T at 4.2 K and an extrapolated value of Hc2(0) above 43 T at 0 K are reported. Films of magnesium plus boron were deposited on unheated c-plane sapphire substrates by co-evaporation, and were subsequently annealed in a reducing atmosphere at temperatures below 600 °C. The use of a combination of a magnesium-rich stoichiometry (Mg/B>1/2) for the as-deposited film and a two-step annealing process was found to be critical in obtaining these high values of Hc2 and |dHc2/dT|Tc|.",

author = "Y. Shen and R. Gandikota and Rakesh Singh and Hunte, {F. L.} and J. Jaroszynski and Larbalestier, {D. C.} and Rowell, {J. M.} and Nathan Newman",

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T1 - A novel technique for synthesizing MgB2 thin films with high upper critical fields

AU - Shen, Y.

AU - Gandikota, R.

AU - Singh, Rakesh

AU - Hunte, F. L.

AU - Jaroszynski, J.

AU - Larbalestier, D. C.

AU - Rowell, J. M.

AU - Newman, Nathan

PY - 2008/8/1

Y1 - 2008/8/1

N2 - We report a new method for synthesizing magnesium diboride (MgB 2) thin films which exhibit a steep increase in the slope of the upper critical field Hc2 versus decreasing temperature (i.e. |dH c2/dT|Tc|≈2.5 T K-1). An Hc2 of 38.4 T at 4.2 K and an extrapolated value of Hc2(0) above 43 T at 0 K are reported. Films of magnesium plus boron were deposited on unheated c-plane sapphire substrates by co-evaporation, and were subsequently annealed in a reducing atmosphere at temperatures below 600 °C. The use of a combination of a magnesium-rich stoichiometry (Mg/B>1/2) for the as-deposited film and a two-step annealing process was found to be critical in obtaining these high values of Hc2 and |dHc2/dT|Tc|.

AB - We report a new method for synthesizing magnesium diboride (MgB 2) thin films which exhibit a steep increase in the slope of the upper critical field Hc2 versus decreasing temperature (i.e. |dH c2/dT|Tc|≈2.5 T K-1). An Hc2 of 38.4 T at 4.2 K and an extrapolated value of Hc2(0) above 43 T at 0 K are reported. Films of magnesium plus boron were deposited on unheated c-plane sapphire substrates by co-evaporation, and were subsequently annealed in a reducing atmosphere at temperatures below 600 °C. The use of a combination of a magnesium-rich stoichiometry (Mg/B>1/2) for the as-deposited film and a two-step annealing process was found to be critical in obtaining these high values of Hc2 and |dHc2/dT|Tc|.

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ER -

A novel technique for synthesizing MgB₂ thin films with high upper critical fields

Abstract

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