ChemInform Abstract: MgB<sub>2</sub> Superconducting Thin Films with a Transition Temperature of 39 Kelvin.

Kang, Won Nam; Kim, Hyeong‐Jin; Choi, Eun‐Mi; Jung, C. U.; Lee, Sung‐Ik

doi:10.1002/chin.200140016

Cited by 5 publications

(11 citation statements)

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“…irreversible field or the upper critical field in superconductors having strong pinning sources [61,64]. The values of K s are determined from the slopes of the F pb 0.5 (1 -b) 2 curves, and it scales as K s (1 -t) 1.7 , which agrees with the temperature dependence of F p,max shown in the inset of Fig. 11(b).…”

Section: Mgb 2 Columnar Thick Filmssupporting

confidence: 73%

“…Kramer described the dynamic pinning force density (F s ) by flux-line lattice (FLL) shearing, which assumed synchronous shear of the FLL around pins too strong to be broken, given by the relation of F s (b) = K s b 0.5 (1 -b) 2 at high fields, where the parameter K s is related to the shear strength [63]. This formula has been widely used for scaling the flux pinning force and for estimating the .…”

Section: Mgb 2 Columnar Thick Filmsmentioning

confidence: 99%

“…The discovery of superconductivity in MgB 2 with a transition temperature (T c ) of 39 K [1,2] is the greatest advantage over conventional metallic superconductors, such as NbTi (T c = 9 K) and Nb 3 Sn (T c = 18 K). In addition, long coherence length [3], high critical current densities [4], and strongly linked nature of the intergrains [5] with a high charge carrier density [6] portrays MgB 2 as a potential material for applications, such as superconducting magnets, electronic devices, and coated conductor wires for power applications [7].…”

Section: Introductionmentioning

confidence: 99%

“…A variety of thin film techniques have been used to grown MgB 2 thin films, such as co-evaporation [13,14], pulse laser deposition (PLD) [2,15], sputtering [16,17], molecular beam epitaxy (MBE) [18][19][20], laser-assisted chemical vapor deposition (LACVD) [21,22], and hybrid physical-chemical vapor deposition (HPCVD) [12,23]. Among all these techniques, HPCVD has been proved to be the most effective one for the fabrication of high-quality MgB 2 films with superior superconducting properties.…”

Section: Introductionmentioning

confidence: 99%

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A review on the understanding and fabrication advancement of MgB₂thin and thick films by HPCVD

Ranot¹,

Duong²,

Bhardwaj³

et al. 2015

Progress in Superconductivity and Cryogenics

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MgB 2 thin films with superior superconducting properties are very promising for superconducting magnets, electronic devices and coated conductor electric power applications. A clear understanding of flux pinning mechanism in MgB 2 films could be a big aid in improving the performance of MgB 2 by the enhancement of J c . The fabrication advancement and the understanding of flux pinning mechanism of MgB 2 thin and thick films fabricated by using hybrid physical-chemical vapor deposition (HPCVD) are reviewed. The distinct kind of MgB 2 films, such as single-crystal like MgB 2 thin films, MgB 2 epitaxial columnar thick films, and a-axis-oriented MgB 2 films are included for flux pinning mechanism investigation. Various attempts made by researchers to improve further the flux pinning property and J c performance by means of doping in MgB 2 thin films by using HPCVD are also summarized.Keywords: MgB2 thin and thick films, HPCVD, flux pinning mechanism * Corresponding author: email: wnkang@skku.edu A review on the understanding and fabrication advancement of MgB2 thin and thick films by HPCVD CCs showed self-field J c values of the order of 10 7 A/cm 2 at 5 K as high as already obtained in MgB 2 thin films, however, J c decreases in response to an applied magnetic field [31,32]. Therefore, a complete understanding of the flux pinning mechanism could be a big aid in improving the performance of MgB 2 by the enhancement of J c , which is most important parameter in practical applications for an operation with low noise and lower power loss. The epitaxial MgB 2 thin films with uniform orientation of grains provide an ideal condition for investigating the vortex dynamics and flux pinning properties, in contrast to MgB 2 bulk system where grains are randomly orientated. In this article, we review the progress made in the last 14 years for the fabrication, understanding of flux pinning mechanism, and for improving the performance by doping in MgB 2 epitaxial thin and thick films by using HPCVD technique.

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Section: Mgb 2 Columnar Thick Filmssupporting

confidence: 73%

Section: Mgb 2 Columnar Thick Filmsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A review on the understanding and fabrication advancement of MgB₂thin and thick films by HPCVD

Ranot¹,

Duong²,

Bhardwaj³

et al. 2015

Progress in Superconductivity and Cryogenics

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“…The remarkably high transition temperature (T c = 39 K) of MgB 2 makes it practically more advantageous over conventional metallic superconductors [1]. The strongly linked nature of the intergrains with a high charge carrier density in this material makes it further an attractive candidate for the next generation of superconductor applications.…”

Section: Introductionmentioning

confidence: 99%

Significant enhancement of critical current density by effective carbon-doping in MgB₂thin films

Ranot¹,

Lee²,

Kang³

2013

Progress in Superconductivity and Cryogenics

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The pure and carbon (C)-doped MgB 2 thin films were fabricated on Al 2 O 3 (0001) substrates at a temperature of 650 °C by using hot-filament-assisted hybrid physical-chemical vapor deposition technique. The T c value for pure MgB 2 film is 38.5 K, while it is between 30 and 35 K for carbon-doped MgB 2 films. Expansion in c-axis lattice parameter was observed with increase in carbon doping concentration which is in contrast to carbon-doped MgB 2 single crystals. Significant enhancement in the critical current density was obtained for C-doped MgB 2 films as compared to the undoped MgB 2 film. This enhancement is most probably due to the incorporation of C into MgB 2 and the high density of grain boundaries, both help in the pinning of vortices and result in improved superconducting performance.

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Exfoliation of Quasi-Two-Dimensional Nanosheets of Metal Diborides

et al. 2021

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The metal diborides are a class of ceramic materials with crystal structures consisting of hexagonal sheets of boron atoms alternating with planes of metal atoms held together with mixed character ionic/covalent bonds. Many of the metal diborides are ultrahigh temperature ceramics like HfB2, TaB2, and ZrB2, which have melting points above 3000ºC, high mechanical hardness and strength at high temperatures, and high chemical resistance, while MgB2 is a superconductor with a transition temperature of 39 K. Here we demonstrate that this diverse family of non-van der Waals materials can be processed into stable dispersions of two-dimensional (2D) nanosheets using ultrasonication-assisted exfoliation. We generate 2D nanosheets of the metal diborides AlB2, CrB2, HfB2, MgB2, NbB2, TaB2, TiB2, and ZrB2, and use electron and scanning probe microscopies to characterize their structures, morphologies, and compositions. The exfoliated layers span up to micrometers in lateral dimension and reach thicknesses down to 2-3 nm, while retaining their hexagonal atomic structure and chemical composition. We exploit the convenient solution-phase dispersions of exfoliated CrB2 nanosheets to incorporate them directly into polymer composites. In contrast to the hard and brittle bulk CrB2, we find that CrB2 nanocomposites remain very flexible and simultaneously provide increases in the elastic modulus and the ultimate tensile strength of the polymer. The successful liquid-phase production of 2D metal diborides enables their processing using scalable low-temperature solution-phase methods, extending their use to previously unexplored applications, and reveals a new family of non-van der Waals materials that can be efficiently exfoliated into 2D forms.The metal diborides are a family of ceramic compounds with the general formula MB2, where M can be a variety of metals from Groups II, IVB and VB such as Hf, Cr, Ti, Zr, Mg, etc.The most common crystal structure for these materials is the AlB2 type, belonging to the P6/mmm space group symmetry, which has the boron atoms in covalently bound hexagonal sheets separated by layers of close-packed metal atoms, 1 as shown in Figure 1a. The interactions between the

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ChemInform Abstract: MgB₂ Superconducting Thin Films with a Transition Temperature of 39 Kelvin.

Cited by 5 publications

References 1 publication

A review on the understanding and fabrication advancement of MgB₂thin and thick films by HPCVD

A review on the understanding and fabrication advancement of MgB₂thin and thick films by HPCVD

Significant enhancement of critical current density by effective carbon-doping in MgB₂thin films

Exfoliation of Quasi-Two-Dimensional Nanosheets of Metal Diborides

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ChemInform Abstract: MgB2 Superconducting Thin Films with a Transition Temperature of 39 Kelvin.

Cited by 5 publications

References 1 publication

A review on the understanding and fabrication advancement of MgB2thin and thick films by HPCVD

A review on the understanding and fabrication advancement of MgB2thin and thick films by HPCVD

Significant enhancement of critical current density by effective carbon-doping in MgB2thin films

Exfoliation of Quasi-Two-Dimensional Nanosheets of Metal Diborides

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Product

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ChemInform Abstract: MgB₂ Superconducting Thin Films with a Transition Temperature of 39 Kelvin.

A review on the understanding and fabrication advancement of MgB₂thin and thick films by HPCVD

A review on the understanding and fabrication advancement of MgB₂thin and thick films by HPCVD

Significant enhancement of critical current density by effective carbon-doping in MgB₂thin films