II. Applications of the Josephson Effect

R. Gross, A. Marx, and F. Deppe © Walther-Meißner-Institut (2001 - 2013)
4.2.2 Operation and Performance of rf SQUIDs
AS-Chap. 4 - 37
dependence of V T on © S and © rf :
- start at © S = n¢© 0 , n = 0:
- V T increases linearly with I rf as long as © rf = MQI rf < © ext,c
- critical rf-current: I rf,c = © ext,c /M
- tank voltage:
for I rf > I rf,c : jump to k = +1 or k = -1 branch
hysteresis loop, energy loss, decrease of rf-current
no hysteresis loops until tank circuit has recovered
further increase of I rf (A B)
transitions at higher rate
at I rf,r : 1 transition in each rf cycle
start at © S = (n+1/2)¢© 0 , n = 0:
transition to k = +1 branch at: © ext,c - © 0 /2
transition to k = -1 branch at:- (© ext,c +© 0 )/2
first horizontal branch at: