Anisotropy and critical current density of MgB2 thin films grown in-situ by molecular beam epitaxy

W. Jo; M. R. Beasley; R. H. Hammond

doi:10.1109/TASC.2003.812216

Anisotropy and critical current density of MgB₂ thin films grown in-situ by molecular beam epitaxy

W. Jo, M. R. Beasley, R. H. Hammond

Department of Physics

Research output: Contribution to journal › Conference article › peer-review

7 Scopus citations

Abstract

We report transport properties of superconducting MgB₂ thin films in-situ grown by molecular beam epitaxy. The MgB₂ films show a superconducting transition at 34.5 K with δT_c < 1 K. We measure the in-plane electrical resistivity of the films in magnetic field to 8 T and estimate the upper critical field H_c2^⊥(0) ∼ 32 T for field oriented along the c-axis and H_c2^∥(0) ∼ 35 T in the plane of the film. We find the zero-temperature coherence lengths ξ_c(0) ∼ 31 Å and ξ_ab(0) ∼ 36 Å, indicating the field anisotropy ratio is 1.2, comparable with reported in-situ epitaxial thin films, but less than single crystals. The calculated electronic mean free path l = 25 Å is smaller than the coherence length, which places our films in the dirty limit. Estimates of the critical current density, J_c, using magnetic field hysteresis loops and the Bean critical state model give nominal critical current densities on the order of 10⁶ A/cm² at 15 K and self-field.

Original language	English
Pages (from-to)	3257-3260
Number of pages	4
Journal	IEEE Transactions on Applied Superconductivity
Volume	13
Issue number	2 III
DOIs	https://doi.org/10.1109/TASC.2003.812216
State	Published - Jun 2003
Event	2002 Applied Superconductivity Conference - Houston, TX, United States Duration: 4 Aug 2002 → 9 Aug 2002

Bibliographical note

Funding Information:
Manuscript received August 5, 2002. This work was supported by the Air Force Office of Scientific Research under Grant F49620-01-0103. The authors are with Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305-4045 USA (e-mail: [email protected]; [email protected]; [email protected]). Digital Object Identifier 10.1109/TASC.2003.812216

Keywords

Anisotropy of coherence length
Critical current density
In-situ growth
MgB thin films
Molecular beam epitaxy

Access to Document

10.1109/TASC.2003.812216

Cite this

@article{798425aa4ff846868648f363dcc32d03,

title = "Anisotropy and critical current density of MgB2 thin films grown in-situ by molecular beam epitaxy",

abstract = "We report transport properties of superconducting MgB2 thin films in-situ grown by molecular beam epitaxy. The MgB2 films show a superconducting transition at 34.5 K with δTc < 1 K. We measure the in-plane electrical resistivity of the films in magnetic field to 8 T and estimate the upper critical field Hc2⊥(0) ∼ 32 T for field oriented along the c-axis and Hc2∥(0) ∼ 35 T in the plane of the film. We find the zero-temperature coherence lengths ξc(0) ∼ 31 {\AA} and ξab(0) ∼ 36 {\AA}, indicating the field anisotropy ratio is 1.2, comparable with reported in-situ epitaxial thin films, but less than single crystals. The calculated electronic mean free path l = 25 {\AA} is smaller than the coherence length, which places our films in the dirty limit. Estimates of the critical current density, Jc, using magnetic field hysteresis loops and the Bean critical state model give nominal critical current densities on the order of 106 A/cm2 at 15 K and self-field.",

keywords = "Anisotropy of coherence length, Critical current density, In-situ growth, MgB thin films, Molecular beam epitaxy",

author = "W. Jo and Beasley, {M. R.} and Hammond, {R. H.}",

note = "Funding Information: Manuscript received August 5, 2002. This work was supported by the Air Force Office of Scientific Research under Grant F49620-01-0103. The authors are with Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305-4045 USA (e-mail: [email protected]; [email protected]; [email protected]). Digital Object Identifier 10.1109/TASC.2003.812216; 2002 Applied Superconductivity Conference ; Conference date: 04-08-2002 Through 09-08-2002",

year = "2003",

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language = "English",

volume = "13",

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T1 - Anisotropy and critical current density of MgB2 thin films grown in-situ by molecular beam epitaxy

AU - Jo, W.

AU - Beasley, M. R.

AU - Hammond, R. H.

N1 - Funding Information: Manuscript received August 5, 2002. This work was supported by the Air Force Office of Scientific Research under Grant F49620-01-0103. The authors are with Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305-4045 USA (e-mail: [email protected]; [email protected]; [email protected]). Digital Object Identifier 10.1109/TASC.2003.812216

PY - 2003/6

Y1 - 2003/6

N2 - We report transport properties of superconducting MgB2 thin films in-situ grown by molecular beam epitaxy. The MgB2 films show a superconducting transition at 34.5 K with δTc < 1 K. We measure the in-plane electrical resistivity of the films in magnetic field to 8 T and estimate the upper critical field Hc2⊥(0) ∼ 32 T for field oriented along the c-axis and Hc2∥(0) ∼ 35 T in the plane of the film. We find the zero-temperature coherence lengths ξc(0) ∼ 31 Å and ξab(0) ∼ 36 Å, indicating the field anisotropy ratio is 1.2, comparable with reported in-situ epitaxial thin films, but less than single crystals. The calculated electronic mean free path l = 25 Å is smaller than the coherence length, which places our films in the dirty limit. Estimates of the critical current density, Jc, using magnetic field hysteresis loops and the Bean critical state model give nominal critical current densities on the order of 106 A/cm2 at 15 K and self-field.

AB - We report transport properties of superconducting MgB2 thin films in-situ grown by molecular beam epitaxy. The MgB2 films show a superconducting transition at 34.5 K with δTc < 1 K. We measure the in-plane electrical resistivity of the films in magnetic field to 8 T and estimate the upper critical field Hc2⊥(0) ∼ 32 T for field oriented along the c-axis and Hc2∥(0) ∼ 35 T in the plane of the film. We find the zero-temperature coherence lengths ξc(0) ∼ 31 Å and ξab(0) ∼ 36 Å, indicating the field anisotropy ratio is 1.2, comparable with reported in-situ epitaxial thin films, but less than single crystals. The calculated electronic mean free path l = 25 Å is smaller than the coherence length, which places our films in the dirty limit. Estimates of the critical current density, Jc, using magnetic field hysteresis loops and the Bean critical state model give nominal critical current densities on the order of 106 A/cm2 at 15 K and self-field.

KW - Anisotropy of coherence length

KW - Critical current density

KW - In-situ growth

KW - MgB thin films

KW - Molecular beam epitaxy

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DO - 10.1109/TASC.2003.812216

M3 - Conference article

AN - SCOPUS:0042475494

SN - 1051-8223

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SP - 3257

EP - 3260

JO - IEEE Transactions on Applied Superconductivity

JF - IEEE Transactions on Applied Superconductivity

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T2 - 2002 Applied Superconductivity Conference

Y2 - 4 August 2002 through 9 August 2002

ER -