Stabilization of Cu-Ni based persistent current switch

Thin-Film Persistent Current Switch

“…We set design goals 1 of a response time less than 10 s and a maximum power of 10 W. This performance is significantly better than previously reported by other workers [4], [5], whose switches required more than 10 W to operate, or had a response time longer than 10 s. The thin-film heat switch shown in Fig. 1(b) easily meets these requirements.…”

“…The resulting ordinary differential equation can be solved for the above boundary conditions by separation of variables. The temperature is 8 (4) For steady-state conditions, i.e., , this reduces to (5) According to (5), for a fixed heat switch geometry, the power depends linearly on , i.e., an increase in requires an equivalent increase in . This means that for a silicon substrate, with to W m K between 4 and 10 K [10], the heat switch would operate at a power which is approximately 1000 to 6000 times larger than borosilicate glass.…”

“…Based on this previous work, we first tried copper alloy heaters. 5 A copper alloy film 100 nm thick was evaporated onto the silicon nitride. After a few thermal cycles, the copper alloy heaters failed (open circuit) apparently due to poor adhesion.…”

Current distribution characteristics of superconducting parallel circuits

“…In order to investigate such superconducting parallel circuits, it becomes necessary to measure the current distribution during the current sweep, the quench process, or the persistent mode. So far, several studies about the current distribution properties of superconducting parallel circuits have been presented [ 1]- [6]. For the current measurement, two methods of a device with the Hall probe [l] and Rogowski coil [2], [4]- [6] were mainly used.…”

“…So far, several studies about the current distribution properties of superconducting parallel circuits have been presented [ 1]- [6]. For the current measurement, two methods of a device with the Hall probe [l] and Rogowski coil [2], [4]- [6] were mainly used.…”