RSFQ Circuitry Using Intrinsic <formula formulatype="inline"> <tex>$\pi$</tex> </formula>-Phase Shifts

Abstract

The latching of temporary data is essential in the Rapid Single Flux Quantum (RSFQ) electronics family. Its pulse-driven nature requires two or more stable states in almost all cells. Storage loops must be designed to have exactly two stable states for binary data representation. In conventional RSFQ such loops are constructed to have two stable states, e.g. by using asymmetric bias currents. This bistability naturally occurs when phase-shifting elements are included in the circuitry, such as-Josephson junctions or a-phase shift associated with an unconventional (-wave) order parameter symmetry. Both approaches can be treated completely analogously, giving the same results. We have demonstrated for the first time the correct operation of a logic circuit, a toggle-flip-flop, using rings with an intrinsic-phase shift (-rings) based on hybrid high-to low-Josephson junctions. Because of their natural bistability these-rings improve the device symmetry, enhance operation margins and alleviate the need for bias current lines.

High-T c Josephson junctions

“…Ortlepp et al (2007) and references therein. For large junction arrays this requires a small spread of single junction parameters like I c and R N .…”

“…This can be used for different RSFQ circuits like a toggle-flip-flop (TFF) demonstrated by Ortlepp et al (2007). Spontaneously generated half-flux quanta are the basis for building a bistable system in which the polarity of the flux is controllable by a current pulse.…”

Existence and stability analysis of finite0−π−0Josephson junctions

“…10 All these findings have promising applications in information storage and information processing. 11,12 This system, in which neighboring facets of a Josephson junction are considered to have opposite signs of the critical current, present intriguing phenomena such as the intrinsic frustration of the Josephson phase over the junction and the spontaneous generation of a fractional magnetic flux at the discontinuities, that is, the positions of the jumps in the Josephson phase. 13,14 In the present work, we consider the so-called 0--0 Josephson junctions on a finite domain, modeled by a modified sine-Gordon equation with phase shift of = in some region and zero otherwise.…”

Transport properties of bi-epitaxialYBa2Cu3O7−δgrain boundary Josephson junctions: Experimental evidence of a subdominant sup

“…15,16 The faceting effect is believed to be controlled by the YBCO growth mechanism on the two electrodes of the junctions and the quality of the substrate grain boundary interfaces. Bicrystal junctions that have been widely used to study the transport properties of grain boundary junctions as substrates with different tilting orientations are available commercially.…”