Abstract:The ability to carry transport current in a magnetic field is the most important aspect of a superconductor. We present a detailed analysis of the upper critical field (H c2 (0)) and vortex dynamics in superconducting boron doped diamond (BDD) films. H c2 (0) measured on the samples of different doping levels revealed a high critical field of up to 7.3 T. Pinning potential U 0 , estimated using thermally activated flux-flow (TAFF) model shows that U 0 is of the order of 10 2 K. Self-field critical current dens… Show more
“…Consideration of other type II superconductors, both materials considered to be conventional [18][19][20][21] and unconventional [15,16,22,23], confirm our argument: broadening of the resistive transition in a field is a universal property of type II superconductors. We are not aware of a single example in the scientific literature showing a resistive transition in magnetic field of any type II superconductor that would be nearly as sharp as shown in Ref.…”
The long-sought goal of room temperature superconductivity has reportedly recently been realized in a carbonaceous sulfur hydride compound under high pressure, as reported by Snider et al [1]. The evidence presented in that paper is stronger than in other similar recent reports of high temperature superconductivity in hydrides under high pressure [2-7], and has been received with universal acclaim [8-10]. Here we point out that features of the experimental data shown in Ref. [1] indicate that the phenomenon observed in that material is not superconductivity. This observation calls into question earlier similar claims of high temperature conventional superconductivity in hydrides under high pressure based on similar or weaker evidence [2][3][4][5][6][7].
“…Consideration of other type II superconductors, both materials considered to be conventional [18][19][20][21] and unconventional [15,16,22,23], confirm our argument: broadening of the resistive transition in a field is a universal property of type II superconductors. We are not aware of a single example in the scientific literature showing a resistive transition in magnetic field of any type II superconductor that would be nearly as sharp as shown in Ref.…”
The long-sought goal of room temperature superconductivity has reportedly recently been realized in a carbonaceous sulfur hydride compound under high pressure, as reported by Snider et al [1]. The evidence presented in that paper is stronger than in other similar recent reports of high temperature superconductivity in hydrides under high pressure [2-7], and has been received with universal acclaim [8-10]. Here we point out that features of the experimental data shown in Ref. [1] indicate that the phenomenon observed in that material is not superconductivity. This observation calls into question earlier similar claims of high temperature conventional superconductivity in hydrides under high pressure based on similar or weaker evidence [2][3][4][5][6][7].
“…Till date, homoepitaxial (111) films have demonstrated the highest offset superconducting transition temperature of up to T c,zero = 10.2 K [72][73][74]. However, for the granular BDD films the transition temperatures are usually less (∼3-7 K) [75][76][77][78].…”
Section: P-type Diamond: Boron Dopingmentioning
confidence: 99%
“…Diamond with its large bandgap (∼5.5 eV) is one of the best electrical insulators (ρ ∼ 10 14 Ω m), however as explained in the previous sections, doping diamond can transform it either into semiconducting or disordered-metallic states. Superconductivity occurs in heavily doped boron doped microcrystalline (MCD) and nano-crystalline diamond (NCD) films (T c ∼ 2.8-7.2 K) [11,78,79]. It is interesting to note that boron-doped NCD films exhibit modulation of the superconducting order parameter between grains, strong superconducting fluctuations, and substantial tunneling between grains in the superconducting state-all these observation are consistent with the strong granular nature of superconductivity in diamond as shown in figure 3 [80,81].…”
Section: Importance Of Boron Doped Granular Superconductor For Quantu...mentioning
confidence: 99%
“…Apart from single-crystalline diamond films, Josephson junctions can also be fabricated on polycrystalline diamond films. Many groups have successfully optimized the growth conditions in hot filament CVD to get good quality BDD films (micro-, nano-, and ultra-nanocrystalline films) [78]. The team demonstrated superconductivity in BDD thick films (60 µm) at ∼4 K [82].…”
Section: Superconducting Boron-doped-diamond (Bdd) As High-performanc...mentioning
Diamond due to its outstanding optical, electrical, mechanical and thermal properties finds an important place in electronic, opto-electronic and quantum technologies. Recent progresses showing superconductivity in diamond by boron doping has opened up many avenues including its applications in SQUID devices especially with polycrystalline diamond films. Granular boron doped diamond films find applications in quantum inductance devices where high surface inductance is required. Particularly important are the defect centers in diamond like nitrogen-vacancy (N-V), silicon vacancy (SiV) and other color centres which are ideal candidates for next generation quantum hardware systems. For efficient device applications, an indispensable need remains for a substitutional donor in diamond lattice that yields a lower thermal activation energy at room temperature. In this review, a comprehensive summary of research and the technological challenges has been reported including some of our latest results on nitrogen doping in polycrystalline diamond to understand the transport phenomenon emphasizing on its possible future applications.
“…Boron doped diamond films (films "A","B", and "C") were deposited using the hot filament chemical vapor deposition (HFCVD) technique [27][28][29] . The silicon substrate temperature was maintained at 850 • C and pressure of the chamber was ∼ 7 Torr.…”
Boron-doped diamond granular thin films are known to exhibit superconductivity with an optimal critical temperature of T c = 7.2K. Here we report the measured complex surface impedance of Boron-doped diamond films in the microwave frequency range using a resonant technique. Experimentally measured inductance values are in good agreement with estimates obtained from the normal state sheet resistance of the material. The magnetic penetration depth temperature dependence is consistent with that of a fully-gapped s-wave superconductor. Boron-doped diamond films should find application where high kinetic inductance is needed, such as microwave kinetic inductance detectors and quantum impedance devices.
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