Related papers: Microwave performance of high-density bulk MgB2
The microwave properties of polycrystalline MgB2 thin films prepared by the so-called in-situ method are investigated. The characterization of the films at microwave frequencies was obtained by a coplanar resonator technique. The analysis…
We report on the results of a comparative investigation of highly dense bulk MgB$_2$ samples prepared by three methods: (i) hot deformation; (ii) high pressure sintering; and (iii) mechanical alloying of Mg and B powders with subsequent hot…
The linear microwave response of ultra high-quality YBa$_2$Cu$_3$O$_x$ single crystals grown in BaZrO$_3$ crucibles is measured at 9.4 GHz in rf magnetic fields parallel and perpendicular to the $ab$-plane in the temperature range 5$\leq…
We propose and demonstrate a spatial partition method for the high-frequency photo-response of superconducting devices correlated with inductive and resistive changes in microwave impedance. Using a laser scanning microscope, we show that…
In this paper, we apply the two-band extension [1] of BCS theory [2] into the Mattis-Bardeen theory [3] to obtain the surface impedance of a two-band superconductor, and apply it to magnesium diboride (MgB2) for radiofrequency (RF)…
Using the dielectric resonator method, we have investigated nonlinearities in the surface impedance Zs = Rs + jXs of YBa2Cu3O7 thin films at 10 GHz as function of the incident microwave power level and temperature. The use of a rutile…
We present a method to measure the absolute surface resistance of conductive samples at a set of GHz frequencies with superconducting lead stripline resonators at temperatures 1- 6K. The stripline structure can easily be applied for bulk…
In order to increase the accelerating gradient of Superconducting Radio Frequency (SRF) cavities, Magnesium Diboride (MgB2) opens up hope because of its high transition temperature and potential for low surface resistance in the high RF…
We report self-consistent {\it ab initio} calculations of structural and electronic properties for the B- and Mg-terminated MgB$_{2}$ (0001) surfaces. We employ ultra-soft pseudopotentials and plane wave basis sets within the generalized…
In this paper, a low profile dynamically tunable microwave absorber is proposed, which consists of high impedance surface (HIS) and graphene sandwich structure (GSS). We theoretically demonstrate and experimentally verify that the proposed…
We have investigated the nonlinear surface impedance and two-tone intermodulation distortion of nine epitaxial YBa2Cu3O7-d films on MgO substrates, using stripline resonators, at frequencies f=2.3-11.2GHz and temperatures T=1.7K-Tc. The…
Surface impedance measurements of LuNi2B2C superconducting thin films as a function of temperature have been performed down to 1.5 K and at 20 GHz using a dielectric resonator technique. The magnetic penetration depth closely reproduces the…
We describe quantitative imaging of the sheet resistance of metallic thin films by monitoring frequency shift and quality factor in a resonant scanning near-field microwave microscope. This technique allows fast acquisition of images at…
We investigate advanced CMOS-compatible Graphene/Silicon active metasurfaces based on guided-mode resonance filters. The simulated results show a high extinction ratio (>25 dB), narrow linewidth (~1.5 nm @1550 nm), quality factor of Q~1000,…
In this letter, we report a method to control reflection phase of microwaves using electrically tunable graphene devices. The device consists of mutually gated large-area graphene layers placed at a quarter-wave distance from a metallic…
We have developed scanning near-field microwave microscopes which can image electrodynamic properties of superconducting materials on length scales down to about 2 $\mu$m. The microscopes are capable of quantitative imaging of sheet…
We describe near-field imaging of sample sheet resistance via frequency shifts in a resonant coaxial scanning microwave microscope. The frequency shifts are related to local sample properties, such as surface resistance and dielectric…
Microwave reflectance probed photoconductivity (or $\mu$-PCD) measurement represents a contactless and non-invasive method to characterize impurity content in semiconductors. Major drawbacks of the method include a difficult separation of…
We have investigated the nonlinear microwave properties of electron-beam coevaporated YBaCuO films on MgO, using stripline resonators at 2.3 GHz and temperatures 1.7-80 K. The oxygen content of the films ranged from strongly underdoped to…
Precision measurements of active and reactive components of in-plane microwave surface impedance were performed in single crystals of optimally-doped Fe-based superconductor Ba(Fe1-xCox)2As2 (x = 0.074, Tc = 22.8 K). Measurements in a…