SQUID Magnetometer for Mangetization Measurements

Abstract
A magnetometer using a symmetric rf-biased SQUID (Superconducting quantum interference device) is described. The instrument has been designed for magnetization measurements of small single crystals at low magnetic fields in the temperature range 4.2-400 K. At low temperatures the sensitivity in magnetic moments is 2 × 10-12 Am2 or 2 × 10-9 emu, which is equivalent to Δχ = 10-7 SI with sample volume 3 mm3 at 0.01 T (100 Oe).