ИСТИНА

Bi-SQUID is a well-known device for highly linear conversion of magnetic field into voltage. The device has already been realized using niobium fabrication process. A high-temperature superconductor (HTS) amplifier is now deemed as one of the highly demanded applications of the circuit. We analyze and discuss design issues of such a HTS bi-SQUID with bi-crystal Josephson junctions. As far as the junction fabrication technique implies the using of a bi-crystal thin film formed on a bi-crystal substrate, this puts rigid restrictions on possible design of the one-layer circuit. In fact, all Josephson junctions are bridges over the same bi-crystal boundary and therefore the bi-SQUID circuit cannot be realized without additional junction in one of its loops (or in the both). The additional junction is a bottom of some distortion of the voltage response linearity. Possible tradeoff for the circuit design is considered.