Handbook of Superconducting Materials

Cardwell, D. A.; Ginley, David S.

doi:10.1201/9781420034202

Cited by 26 publications

(4 citation statements)

References 357 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Re{Z} is the resistance representing energy losses in the form of heat from collisions. Im{Z} is the reactance arising from charge carrier inertia, a concept widely used in superconductivity [27] and also known as kinetic inductance, L k . Finally, C is the capacitance between spatially separated electrons and holes.…”

Section: Resultsmentioning

confidence: 99%

Terahertz photoconductive switch performance dependence on antenna shape

Nevinskas,

Kamarauskas,

Geižutis

et al. 2024

Preprint

View full text Add to dashboard Cite

Terahertz photoconductive switch antennas come in many designs that appear to be hardly ever sensibly selected. The femtosecond laser induced carriers generate a continuum at terahertz frequencies that require a low Q factor antenna design achievable through ohmic losses. On the one hand, if a broadband terahertz spectrum is desired, a simple coplanar stripline configuration with narrow arm width, i.e. a short dipole, is sufficient. On the other hand, the practical antenna resonance effect raises fabrication and engineering challenges, while the studied antenna shapes provide only a slight improvement to the emission efficiency. These findings are supported by the terahertz emission and detection characterization of a dozen antenna designs, and the results are discussed through the classical Drude-Lorentz conductivity framework.

show abstract

Section: Resultsmentioning

confidence: 99%

Terahertz photoconductive switch performance dependence on antenna shape

Nevinskas,

Kamarauskas,

Geižutis

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

“…In these experiments, the samples are situated at the center of a solenoid which can generate magnetic fields up to 1200 Oe; reported fields generated by the coil at the sample are calibrated values based upon the current in the solenoid [24]. In the reflective mode with in-plane magnetization, the relationship between microstructural defects and magnetic flux penetration and trapping below the 9.3 K critical temperature (T c ) is directly visualized with an optical microscope [23,[43][44][45][46][47]. While this method was developed for thin films, it has been adapted for thicker samples with an iterative procedure such that aspect ratios of diameter to thickness as low as 3 can provide a resolution of about 30 µm [46].…”

Section: Cryogenic Mo Imaging and Critical Current Density Estimationmentioning

confidence: 99%

“…While this method was developed for thin films, it has been adapted for thicker samples with an iterative procedure such that aspect ratios of diameter to thickness as low as 3 can provide a resolution of about 30 µm [46]. There are three imaging modes: zero-field-cooling (ZFC) mode, remnant field (RF) mode, and field-cooling (FC) mode [19,24,45]. For the ZFC mode, the sample was cooled in a zero magnetic field below T c , and then the external magnetic field was increasingly applied perpendicular to the sample surface.…”

Section: Cryogenic Mo Imaging and Critical Current Density Estimationmentioning

confidence: 99%

“…where F p is the pinning force density, and B is the magnetic flux density. Critical current density can be estimated from MO images by measuring the width of the flux-free Meissner regions [45]. GB transparency (r) is defined as the ratio of the critical current density across the GB J GB c to that within the grain (bulk) J grain c [43,47]:…”

Section: Cryogenic Mo Imaging and Critical Current Density Estimationmentioning

confidence: 99%

See 1 more Smart Citation

Investigation of the effect of structural defects from hydride precipitation on superconducting properties of high purity SRF cavity Nb using magneto-optical and electron imaging methods

Wang

Polyanskii²,

Balachandran³

et al. 2022

Supercond. Sci. Technol.

View full text Add to dashboard Cite

Nb is an elemental superconductor with a critical temperature of 9.3 K and is widely used to fabricate superconducting radiofrequency (SRF) cavities for particle accelerators. However, microstructural defects in Nb, such as grain boundaries and dislocations, can act as pinning centers for magnetic flux that can degrade SRF cavity performance. Hydrogen contamination is also detrimental to SRF cavity performance due to the formation of normal conducting hydrides during cool down. In this study, disc shaped Nb bi-crystals extracted from a high-purity large-grain Nb slice were investigated to study the effects of grain boundaries, hydrogen, and dislocations on superconducting properties. Grain orientation and grain boundary misorientation were measured using Laue X-ray diffraction and electron backscattered diffraction (EBSD) analyses. Cryogenic magneto-optical imaging was used to directly observe magnetic flux penetration below T_c =9.3 K. Damage caused by low temperature precipitation of hydrides and their dissolution upon reheating after cryogenic cycles was examined using electron channeling contrast imaging (ECCI), and EBSD. The relationships between hydride formation, dislocation content, grain boundaries, cryo-cooling, heat treatment, and flux penetration indicate that both grain boundary character and hydrogen content affect magnetic flux penetration. Such flux penetration could be facilitated by dislocation structures and low angle grain boundaries resulting from hydride precipitation and heat treatment.

show abstract

Review and perspective on ultrafast wavelength-size electro-optic modulators

Liu

Khan

et al. 2015

Laser & Photonics Reviews

207

113

View full text Add to dashboard Cite

As electronic device feature sizes scale‐down, the power consumed due to onchip communications as compared to computations will increase dramatically; likewise, the available bandwidth per computational operation will continue to decrease. Integrated photonics can offer savings in power and potential increase in bandwidth for onchip networks. Classical diffraction‐limited photonics currently utilized in photonic integrated circuits (PIC) is characterized by bulky and inefficient devices compared to their electronic counterparts due to weak light–matter interactions (LMI). Performance critical for the PIC is electro‐optic modulators (EOM), whose performances depend inherently on enhancing LMIs. Current EOMs based on diffraction‐limited optical modes often deploy ring resonators and are consequently bulky, photon‐lifetime modulation limited, and power inefficient due to large electrical capacitances and thermal tuning requirements. In contrast, wavelength‐scale EOMs are potentially able to surpass fundamental restrictions set by classical (i.e. diffraction‐limited) devices via (a) high‐index modulating materials, (b) nonresonant field and density‐of‐states enhancements such as found in metal optics, and (c) synergistic onchip integration schemes. This manuscript discusses challenges, opportunities, and early demonstrations of nanophotonic EOMs attempting to address this LMI challenge, and early benchmarks suggest that nanophotonic building blocks allow for densely integrated high‐performance photonic integrated circuits.

show abstract

Handbook of Superconducting Materials

Cited by 26 publications

References 357 publications

Terahertz photoconductive switch performance dependence on antenna shape

Terahertz photoconductive switch performance dependence on antenna shape

Investigation of the effect of structural defects from hydride precipitation on superconducting properties of high purity SRF cavity Nb using magneto-optical and electron imaging methods

Review and perspective on ultrafast wavelength-size electro-optic modulators

Contact Info

Product

Resources

About