Fabrication and some properties of biaxially aligned Sr0.6K0.4Fe2As2 superconductors by processing in high magnetic field

Growth of Strongly Biaxially Aligned MgB2 Thin Films on Sapphire by Post-annealing of Amorphous Precursors

MgB2 thin films were cold-grown on sapphire substrates by pulsed laser deposition (PLD), followed by post-annealing in mixed, reducing gas, Mg-rich, Zr gettered, environments. The films had Tcs in the range 29 K to 34 K, Jcs (20K, H=0) in the range 30 kA/cm2 to 300 kA/cm2, and irreversibility fields at 20 K of 4 T to 6.2 T. An inverse correlation was found between Tc and irreversibility field. The films had grain sizes of 0.1-1 micron and a strong biaxial alignment was observed in the 950C annealed film.

A self-aligned nano-fabrication process for vertical NbN-MgO-NbN Josephson junctions

We present a new process for fabricating vertical NbN-MgO-NbN Josephson junctions using self-aligned silicon nitride spacers. It allows for a wide range of junction areas from 0.02 um^2 to several 100 um^2. At the same time, it is suited for the implementation of complex microwave circuits with transmission line impedances ranging from < 1 Ohm to > 1 kOhm. The constituent thin films and the finished junctions are characterized. The latter are shown to have high gap voltages (> 4 mV) and low sub-gap leakage currents.

Self-aligned nanoscale SQUID on a tip

A nanometer-sized superconducting quantum interference device (nanoSQUID) is fabricated on the apex of a sharp quartz tip and integrated into a scanning SQUID microscope. A simple self-aligned fabrication method results in nanoSQUIDs with diameters down to 100 nm with no lithographic processing. An aluminum nanoSQUID with an effective area of 0.034 $μ$m$^2$ displays flux sensitivity of 1.8$\cdot 10^{-6}$ $Φ_0/\mathrm{Hz}^{1/2} and operates in fields as high as 0.6 T. With projected spin sensitivity of 65 $μ_B/\mathrm{Hz}^{1/2}$ and high bandwidth, the SQUID on a tip is a highly promising probe…

钽 Josephson 结构的三明治制备与结构分析：具有Ta₂O₅屏障

Fabrication and Structural Analysis of Trilayers for Tantalum Josephson Junctions with Ta$_2$O$_5$ Barriers

本文提出了一种用于制备清洁界面Josephson结的钽氧化物三明治结构，通过等离子体氧化技术实现了平滑的Ta₂O₅层，并展示了其在超导量子比特中的应用潜力。

Artificially engineered superlattices of pnictide superconductor

Significant progress has been achieved in fabricating high quality bulk and thinfilm iron-based superconductors. In particular, artificial layered pnictide superlattices offer the possibility of tailoring the superconducting properties and understanding the mechanism of the superconductivity itself. For high field applications, large critical current densities (Jc) and irreversibility fields (Hirr) are indispensable along all crystal directions. On the other hand, the development of superconducting devices such as tunnel junctions requires multilayered heterostructures. Here we show that artif…

Scanning nano-SQUID with single electron spin sensitivity

One of the critical milestones in the intensive pursuit of quantitative nanoscale magnetic imaging tools is achieving the level of sensitivity required for detecting the field generated by the spin magnetic moment μB of a single electron. Superconducting quantum interference devices (SQUIDs), which were traditionally the most sensitive magnetometers, could not hitherto reach this goal because of their relatively large effective size (of the order of 1 μm). Here we report self-aligned fabrication of nano-SQUIDs with diameters as small as 46 nm and with an extremely low flux noise of 50 nΦ0/Hz^1…