Coexistence of covalent and metallic bonding in the boron intercalation superconductor<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">MgB</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Belashchenko, Kirill D.; Schilfgaarde, Mark van; Antropov, Vladimir

doi:10.1103/physrevb.64.092503

Cited by 143 publications

(110 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A possible reduction of κ ph with increasing H could slightly change this ratio in favor of κ e,π , but only by a few percent. The ratio κ e,π /κ e,σ is 0.57/0.43, as estimated from the κ(H) data at T = 0.60 K. This ratio is remarkably close to the ratio of the densities of electronic states in the two bands N 0,π /N 0,σ of 0.58/0.42, as calculated by Liu et al 15 and 0.55/0.45 by Belashchenko et al 44 . Similar ratios of 0.55/0.45 and 0.50/0.50 have been extracted from tunneling spectroscopy measurements 43 and from specific heat experiments, 2 respectively.…”

Section: Thermal Conductivity In the Mixed Statesupporting

confidence: 61%

Thermal conductivity of single-crystallineMgB2

et al. 2002

View full text Add to dashboard Cite

The ab-plane thermal conductivity κ of single-crystalline hexagonal MgB2 has been measured as a function of magnetic field H with orientations both parallel and perpendicular to the c-axis and at temperatures between 0.5 and 300 K. In the mixed state, κ(H) measured at constant temperatures reveals features that are not typical for common type-II superconductors. The observed behavior may be associated with the field-induced reduction of two superconducting energy gaps, significantly different in magnitude. A nonlinear temperature dependence of the electronic thermal conductivity is observed in the field-induced normal state at low temperatures. This behavior is at variance with the law of Wiedemann and Franz, and suggests an unexpected instability of the electronic subsystem in the normal state at T ≈ 1 K.

show abstract

Section: Thermal Conductivity In the Mixed Statesupporting

confidence: 61%

Thermal conductivity of single-crystallineMgB2

et al. 2002

View full text Add to dashboard Cite

show abstract

“…To give an example, α-alumina [20] (purity >99.99%) behaves as a mixed conductor, being predominantly an ionic conductor at temperatures below 873°C, an electronic conductor at temperatures higher than 1323°C and a mixed conductor within the two temperatures ranges. Conductivity is influenced by intrinsic material properties such as the electronic structure, nature of bonding [28], presence of defects [29], grain size, stoichiometry, relative density, crystallinity and level of Figure 3. The temperature-dependence of conductivity of typical metallic, semiconductor (narrow and wide band gap) and ionic conductor, W (T m = 3380°C) [21], Cu (T m = 1084°C) [22], B 4.3 C (T m* = 2447°C) [23], SiC (T m* = 2730°C, 3.1 eV) [24], YSZ (T m ≈ 2700°C) [25], BaTiO 3 (T m = 1618°C, 1.55 eV) [26], Al 2 O 3 (T m = 2050°C) [27].…”

Section: Fs: Family Of Materials With Different Conductivity Modes (Ementioning

confidence: 99%

Review of flash sintering: materials, mechanisms and modelling

Grasso

McKinnon

et al. 2016

Advances in Applied Ceramics

401

248

View full text Add to dashboard Cite

Flash sintering (FS) is an energy efficient sintering technique involving electrical Joule heating, which allows very rapid densification (<60 s) of particulate materials. Since the first publication on flash-sintered zirconia (3YSZ) in 2010, it has been intensively researched and applied to a wide range of materials. Going back more than a century ago, we have found a close similarity between FS of oxides and Nernst glowers developed in 1897. This review provides a comprehensive overview of FS and is based on a literature survey consisting of 88 papers and seven patents. It correlates processing parameters (i.e. electric field magnitude, current density, waveforms (AC, DC) and frequency, furnace temperature, electrode materials/ configuration, externally applied pressure and sintering atmosphere) with microstructures and densification mechanisms. Theorised mechanisms driving the rapid densification are substantiated by modelling work, advanced in situ analysis techniques and by established theories applied to electric current assisted/activated sintering techniques. The possibility of applying FS to a wider range of materials and its implementation in industrial scale processes are discussed.

show abstract

“…Soon, the typical and peculiar properties of MgB 2 came into picture like the two band nature having double band gap and the unusual Fermi surface topology. 4,5 Various groups studied the band structure unfolding the mystery of different nature of Fermi surfaces for different 3,4,6,7 bands. MgB 2 has two bands, namely, and .…”

Section: Introductionmentioning

confidence: 99%

Enhanced critical parameters of nanocarbon doped MgB2 superconductor

Mudgel

Chandra

Ganesan

et al. 2009

Journal of Applied Physics

View full text Add to dashboard Cite

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.

show abstract

Coexistence of covalent and metallic bonding in the boron intercalation superconductorMgB2

Cited by 143 publications

References 13 publications

Thermal conductivity of single-crystallineMgB2

Thermal conductivity of single-crystallineMgB2

Review of flash sintering: materials, mechanisms and modelling

Enhanced critical parameters of nanocarbon doped MgB2 superconductor

Contact Info

Product

Resources

About