A LOW-FIELD SUPERCONDUCTING QUANTUM INTERFERENCE DEVICE MAGNETOMETER FOR DYNAMIC MEASUREMENTS

A superconducting quantum interference device magnetometer system desi gned for low field static and dynamic susceptibility measurements is d escribed. Magnetic shields reduce the residual field in the sample spa ce to about 0.04 A/m (0.5 mOe). A highly stable de magnetic field is g enerated by a small superconducting solenoid working in the persistent mode. The temperature control system yields a resolution better than 10 mu K in the range of 30-100 K. Combining ac susceptibility and de m agnetic relaxation measurements, the system allows dynamic susceptibil ity studies in a time window ranging from 3 x 10(-6) to 10(6) s. The s ensitivity of the system is 10(-12) Am-2 (10(-9) emu). (C) 1997 Americ an Institute of Physics.