Direct evidence of microstructure dependence of magnetic flux trapping in niobium.

Elemental type-II superconducting niobium is the material of choice for superconducting radiofrequency cavities used in modern particle accelerators, light sources, detectors, sensors, and quantum computing architecture. An essential challenge to increasing energy efficiency in rf applications is the power dissipation due to residual magnetic field that is trapped during the cool down process due to incomplete magnetic field expulsion. New SRF cavity processing recipes that use surface doping techniques have significantly increased their cryogenic efficiency.

Design and performance of a new induction furnace for heat treatment of superconducting radiofrequency niobium cavities.

Superconducting radio frequency (SRF) cavities made of high purity niobium (Nb) are the building blocks of many modern particle accelerators. The fabrication process includes several cycles of chemical and heat treatment at low (∼120 °C) and high (∼800 °C) temperatures. In this contribution, we describe the design and performance of an ultra-high-vacuum furnace which uses an induction heating system to heat treat SRF cavities.

Ultrasensitive chemical detection using a nanocoax sensor.

We report on the design, fabrication, and performance of a nanoporous, coaxial array capacitive detector for highly sensitive chemical detection. Composed of an array of vertically aligned nanoscale coaxial electrodes constructed with porous dielectric coax annuli around carbon nanotube cores, this sensor is shown to achieve parts per billion level detection sensitivity, at room temperature, to a broad class of organic molecules. The nanoscale, 3D architecture and microscale array pitch of the sensor enable rapid access of target molecules and chip-based multiplexing capabilities, respectively.

Observation and simulation of all angular magnetoresistance oscillation effects in the quasi-one-dimensional organic conductor (DMET)(2)I(3).

Measurements and calculations of magnetotransport in the organic conductor (DMET)(2)I(3) detect and simulate all angular magnetoresistance oscillations known for quasi-one-dimensional conductors. By employing the actual triclinic crystal structure in the calculations, these results address the putative vanishing of the primary magnetoresistance phenomenon, the Lebed magic angle effect, for orientations in which it was expected to be strongest. They also show a common origin for Lebed and the so-called Lee-Naughton oscillations and confirm the generalized nature of angular effects in such systems.