Growth mechanism of superconducting MgB<sub>2</sub> films prepared by various methods

We have performed a comparative study of two thin films of magnesium diboride (MgB 2 ) grown by different techniques. The critical current density at different temperatures and magnetic fields was evaluated from magnetisation curves, the structure of superconducting order parameter was obtained from point-contact spectroscopy, and the scattering rates were evaluated by fitting the temperature dependent normal-state resistivity to the two-band model. The films have similar critical temperatures close to 39 K, but the upper critical fields were different by a factor of 2 (5.2T and 2.5 T at 20 K). We have found that the film with higher H c2 also had stronger scattering in the σ band and smaller value of the superconducting gap in this band. As the scattering in σ band is primarily due to the defects in boron plane, our results are consistent with the assumption that disordering the boron planes leads to enhanced H c2 and better pinning properties in magnetic field.

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“…The details of film preparation are described elsewhere [14]. This is the same film that has been studied in our earlier works [15,16].…”

Section: Samplesmentioning

confidence: 99%

Superconducting gap structure and pinning in disordered MgB₂films

Bugoslavsky¹,

Miyoshi²,

Perkins³

et al. 2004

Supercond. Sci. Technol.

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“…There have already been many reports on the synthesis of superconducting MgB 2 films [2][3][4][5][6][7][8][9][10][11][12][13][14]. There are two complicating problems related to the preparation of superconducting MgB 2 films.…”

Section: Introductionmentioning

confidence: 99%

In situ growth of superconducting MgB2 thin films by molecular-beam epitaxy

Ueda

Naito

2003

Journal of Applied Physics

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The in-situ growth of superconducting MgB 2 thin films was examined from various perspectives. The paper discusses (1) growth temperature, (2) the effect of excess Mg, (3) the effect of residual gas during growth, (4) the effect of in-situ annealing, (5) thickness dependence and (6) the effect of substrates. Our results provide a guide to the preparation of high-quality superconducting MgB 2 films for potential electronics applications.

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“…The surfaces of these films are rough and non-stoichiometric [2,12,14] MgB 2 has many properties that make it very attractive for superconducting electronics. Unlike cuprate high-temperature superconductors, MgB 2 seems to be a phonon-mediated superconductor [15] with a relatively long coherence length [16].…”

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confidence: 99%

In situ epitaxial MgB2 thin films for superconducting electronics

Zeng¹,

Pogrebnyakov²,

Kotcharov³

et al. 2002

Nature Mater

389

307

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A thin film technology compatible with multilayer device fabrication is critical for exploring the potential of the 39-K superconductor magnesium diboride for superconducting electronics. Using a Hybrid Physical-Chemical Vapor Deposition (HPCVD) process, it is shown that the high Mg vapor pressure necessary to keep the MgB 2 phase thermodynamically stable can be achieved for the in situ growth of MgB 2 thin films. The films grow epitaxially on (0001) sapphire and (0001) 4H-SiC substrates and show a bulk-like T c of 39 K, a J c (4.2K) of 1.2 × 10 7 A/cm 2 in zero field, and a H c2 (0) of 29.2 T in parallel magnetic field. The surface is smooth with a root-mean-square roughness of 2.5 nm for MgB 2 films on SiC. This deposition method opens tremendous opportunities for superconducting electronics using MgB 2 .

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Growth mechanism of superconducting MgB₂ films prepared by various methods

Cited by 61 publications

References 10 publications

Superconducting gap structure and pinning in disordered MgB₂films

Superconducting gap structure and pinning in disordered MgB₂films

In situ growth of superconducting MgB2 thin films by molecular-beam epitaxy

In situ epitaxial MgB2 thin films for superconducting electronics

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Growth mechanism of superconducting MgB2 films prepared by various methods

Cited by 61 publications

References 10 publications

Superconducting gap structure and pinning in disordered MgB2films

Superconducting gap structure and pinning in disordered MgB2films

In situ growth of superconducting MgB2 thin films by molecular-beam epitaxy

In situ epitaxial MgB2 thin films for superconducting electronics

Contact Info

Product

Resources

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Growth mechanism of superconducting MgB₂ films prepared by various methods

Superconducting gap structure and pinning in disordered MgB₂films

Superconducting gap structure and pinning in disordered MgB₂films