Harmonic mixing with Josephson point contacts

Carbon nanotube Josephson junctions with Nb contacts

We report on the preparation of carbon nanotube Josephson junctions using superconducting electrodes made of niobium. Gate-controllable supercurrents with values of up to 30 nA are induced by the proximity effect. The IV curves are hysteretic at low temperature and the corresponding switching histograms have a width of 0.5%–2%. An on-chip resistive environment integrated in the sample layout is...

Sensing with Superconducting Point Contacts

Superconducting point contacts have been used for measuring magnetic polarizations, identifying magnetic impurities, electronic structures, and even the vibrational modes of small molecules. Due to intrinsically small energy scale in the subgap structures of the supercurrent determined by the size of the superconducting energy gap, superconductors provide ultrahigh sensitivities for high resolu...

Bi2Sr2CaCu2O8+δ Intrinsic Josephson Junction and Its Application in Harmonic Mixing at the Millimeter Waveband

In this paper, we report the successful fabrication and characteristics of the Bi2Sr2CaCu2O8+δ intrinsic Josephson junctions. To study the microwave influence of these intrinsic junctions, harmonic mixing was carried out in the millimeter waveband at temperature ranging from 20K to 77K. Up to 68 harmonic mixing in the 8 millimeter waveband and 56 in the 3 millimeter waveband were clearly obser...

Multiwall Carbon Nanotube Josephson Junctions with Niobium Contacts

Spin supercurrent in Josephson contacts with noncollinear ferromagnets

We present a theoretical study of the Josephson coupling of two superconductors that are connected through a diffusive contact consisting of noncollinear ferromagnetic domains. The leads are conventional s-wave superconductors with a phase difference of <p. Firstly, we consider a contact with two domains with magnetization vectors misoriented by an angle e. Using the quantum circuit theory, we ...