  The phenomena of intermittent and complete synchronization between two out of
three identical, magnetically coupled SQUIDs (Superconducting QUantum
Interference Devices) are investigated numerically. SQUIDs are highly nonlinear
superconducting oscillators/devices that exhibit strong resonant and tunable
response to applied magnetic field(s). Single SQUIDs and SQUID arrays are
technologically important solid state devices, and they also serve as a testbed
for exploring numerous complex dynamical phenomena. In SQUID oligomers, the
dynamic complexity increases considerably with the number of SQUIDs. The SQUID
trimer, considered here in a linear geometrical configuration using a realistic
model with accesible control parameters, exhibits chaotic and hyperchaotic
behavior in wide parameter regions. Complete chaos synchronization as well as
intermittent chaos synchronization between two SQUIDs of the trimer is
identified and characterized using the complete Lyapunov spectrum of the system
and appropriate measures. The passage from complete to intermittent
synchronization seems to be related to chaos-hyperchaos transitions as has been
conjectured in the early days of chaos synchronization.
