The Variation of Cryotron Current Amplification Factor with Temperature [Letter to the Editor]

The current amplification factor of a shielded, thin-film cryotron has been found to increase as the temperature is reduced below the critical temperature of the gate. From the Silsbee hypothesis,
¹
this factor is the ratio of the gate-film width to the contro -film width. The experimental work shows that the amplification factor is zero at the critical temperature of the gate and rises rapidly in the region when the penetration depth is decreasing, namely just below the critical temperature of the gate.