Upper critical fields in as-grown MgB2 films prepared by ultra-high-vacuum MBE

Noguchi, S.; Kuribayashi, Akihiro; Oba, T.; Iriuda, H.; Harada, Y.; Yoshizawa, Michito; Ishida, Toshimasa

doi:10.1016/j.physc.2007.03.446

Cited by 5 publications

(4 citation statements)

References 11 publications

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“…Thus, GL theory also confirms the enhancement of the H c2 value. The H c2 (0) values determined by us are also in agreement with other reported literature [11,29,30].…”

Section: Magneto-transport and Upper Critical Field (H C2 )supporting

confidence: 92%

The effect of synthesis temperature on the superconducting properties of n-SiC added bulk MgB₂superconductor

Vajpayee¹,

Jha²,

Srivastava³

et al. 2011

Supercond. Sci. Technol.

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We study the effect of synthesis temperature on the phase formation in nano(n)-SiC added bulk MgB 2 superconductor. In particular we study: lattice parameters, amount of carbon (C) substitution, microstructure, critical temperature (T c ), irreversibility field substitution enhances the H c2 while the low temperature synthesis is responsible for the improvement in J c due to the smaller grain size, defects and nano-inclusion induced by C incorporation into MgB 2 matrix, which is corroborated by elaborative HRTEM (highresolution transmission electron microscopy) results. We optimized the the T c (R=0) of above 15K for the studied n-SiC doped and 750 0 C synthesized MgB 2 under 140 KOe field, which is one of the highest values yet obtained for variously processed and nanoparticle added MgB 2 in literature to our knowledge.

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“…Thus, GL theory also confirms the enhancement of the H c2 value. The H c2 (0) values determined by us are also in agreement with other reported literature [11,29,30].…”

Section: Magneto-transport and Upper Critical Field (H C2 )supporting

confidence: 92%

The effect of synthesis temperature on the superconducting properties of n-SiC added bulk MgB₂superconductor

Vajpayee¹,

Jha²,

Srivastava³

et al. 2011

Supercond. Sci. Technol.

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“…It takes into account the impact of both bands on the critical parameters. If we would have applied this model, the H c2 (0) value had been obtained as high as 400 kOe [12,24] in case of bulk and 500 kOe in case of thin films [10,25]. This actually corresponds to the real situation in case of MgB 2 because the negative curvature in H c2 line near T=0 K according to GL equation is not expected.…”

Section: Resultsmentioning

confidence: 90%

Enhanced critical parameters of nanocarbon doped MgB2 superconductor

Mudgel

Chandra

Ganesan

et al. 2009

Journal of Applied Physics

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The high field magnetization and magnetotransport measurements are carried out to determine the critical superconducting parameters of MgB 2−x C x system. The synthesized samples are pure phase and the lattice parameter evaluation is carried out using the Rietveld refinement. The R − T͑H͒ measurements are done up to a field of 140 kOe. The upper critical field values, H c2 , are obtained from these data based on the criterion of 90% of normal resistivity, i.e., H c2 = H at which =90% N , where N is the normal resistivity, i.e., resistivity of about 40K in our case. The Werthamer-Helfand-Hohenberg prediction of H c2 ͑0͒ underestimates the critical field value even below the field up to which measurement is carried out. After this model, the Ginzburg-Landau theory is applied to the R − T͑H͒ data which not only calculate the H c2 ͑0͒ value but also determine the dependence of H c2 on temperature in the low temperature high field region. The estimated H c2 ͑0͒ = 157.2 kOe for pure MgB 2 is profoundly enhanced to 297.5 kOe for the x = 0.15 sample in MgB 2−x C x series. Magnetization measurements are done up to 120 kOe at different temperatures and the other parameters such as irreversibility field H irr and critical current density J c ͑H͒ are also calculated. The nano carbon doping results in substantial enhancement of critical parameters such as H c2 , H irr , and J c ͑H͒ in comparison to the pure MgB 2 sample.

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“…High-quality MgB 2 thin films were prepared by using a multiple-target sputtering system with Mg and 10 B targets at a low substrate temperature on the c-plane of A 2 O 3 substrates [30][31][32][33]. The sample surface thus obtained is extremely smooth so as to be able to allow nanofabrication of MgB 2 films by using electron beam lithography.…”

Section: Superconducting Mgb 2 Stripline Fabricationmentioning

confidence: 99%

Scanning laser microscope for imaging nanostructured superconductors

Ishida

Arai

Akita

et al. 2010

Physica C: Superconductivity

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Upper critical fields in as-grown MgB2 films prepared by ultra-high-vacuum MBE

Cited by 5 publications

References 11 publications

The effect of synthesis temperature on the superconducting properties of n-SiC added bulk MgB₂superconductor

The effect of synthesis temperature on the superconducting properties of n-SiC added bulk MgB₂superconductor

Enhanced critical parameters of nanocarbon doped MgB2 superconductor

Scanning laser microscope for imaging nanostructured superconductors

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Upper critical fields in as-grown MgB2 films prepared by ultra-high-vacuum MBE

Cited by 5 publications

References 11 publications

The effect of synthesis temperature on the superconducting properties of n-SiC added bulk MgB2superconductor

The effect of synthesis temperature on the superconducting properties of n-SiC added bulk MgB2superconductor

Enhanced critical parameters of nanocarbon doped MgB2 superconductor

Scanning laser microscope for imaging nanostructured superconductors

Contact Info

Product

Resources

About

The effect of synthesis temperature on the superconducting properties of n-SiC added bulk MgB₂superconductor

The effect of synthesis temperature on the superconducting properties of n-SiC added bulk MgB₂superconductor