Physikalisches Institut

Electric transport and noise

We do have various experimental setups for measurements of electric transport properties over a wide range of

Fig. 1: Cryostat with superconducting magnet

Depending on requirements for temperature range and stability we use various methods for setting sample temperatures:

a.) pumping on liquid Helium-3(300 mK < T < 1.5 K)

b.) pumping on liquid Helium 4 (1.5 K < T < 4.2 K)

c.) optical laser heating (4.2 K < T< 100 K) for high temperature stabilily (1 mK)

d.) resistive heating of a volume filled by Helium gas („adiabat“) (4.2 K < T< 300 K)

e.) He flow-cryostat: cooling power is controlled by He-flow (4.2 K < T < 300 K)

Fig. 2: Circuit diagram of a SQUID amplifier.