Showing papers by "Keiji Enpuku published in 1996"
TL;DR: In this article, the effects of large dielectric constant of SrTiO3 substrate on the characteristics of high Tc dc superconducting quantum interference device (SQUID) are studied theoretically.
Abstract: Effects of large dielectric constant of SrTiO3 substrate on the characteristics of high Tc dc superconducting quantum interference device (SQUID) are studied theoretically. It is shown that parasitic capacitance, which is caused by the substrate and distributes along an inductance of the SQUID, cannot be neglected when we use SrTiO3 substrate. Due to the distributed parasitic capacitance, the inductance can no longer be described as lumped element, but behaves like a transmission line when the length of the inductance becomes long. Taking into account the resonant characteristics of the transmission line, we have modified the conventional equivalent circuit of the SQUID, and presented a circuit model for this case. Using numerical simulation, we have clarified quantitatively how the SQUID characteristics are affected by the resonance due to the parasitic capacitance. The obtained results indicate the importance of taking into account the resonance when we use the SrTiO3 substrate, especially for the case ...
24 citations
TL;DR: In this paper, the influence of locally applied magnetic field was also studied by utilizing two kinds of junction, i.e., a single layer junction made on a step on an MgO substrate and a multi-layer junction having a control line just below the junctions.
Abstract: Current - voltage characteristics of step-edge junctions made of thin films were studied as a function of magnetic field and temperature within the framework of the Bardeen - Stephen flux flow model. The influence of a locally applied magnetic field was also studied by utilizing two kinds of junction, i.e. a single-layer junction made on a step on an MgO substrate and a multi-layer junction having a control line just below the junctions.
2 citations
Journal Article•
1 citations
01 Jan 1996
TL;DR: In this paper, the effect of resonance, which is caused by high dielectric constant of SrTi03, on the magnetic properties of high Tc dc SQUID was investigated.
Abstract: Characteristics of high Tc dc SQUID, such as transfer function, voltage noise and flux noise, are studied as functions of SQUID parameters. From the comprehensive comparison between theory and experiment parameter dependencies of these characteristics have been clarified. Using these results, we discuss the performance of the SQUID magnetometer, and show optimum values of inductance for making high performance magnetometer. Finally, effect of resonance, which is caused by high dielectric constant of SrTi03, on the SQUID characteristics is shown. It is important to take into account this effect in the design of the SQUID magnetometer.