Development of an extraction type magnetometer under low temperature and high magnetic fields over 20 T by the hybrid magnet

An extraction-type magnetometer has been developed, which is performed under the low temperature of 0.5-0.6 K using a ³He-refrigerator and high magnetic fields up to 18 T using a superconducting magnet (SM) and 27 T using a hybrid magnet (HM). Magnetization curves can be measured with the absolute value over 0.0005 emu using SM and 0.005 emu using HM. We confirmed that the resolution is 0.001 emu for SM and 0.005 emu for HM. For demonstrating the ability of the magnetometer, high field magnetization curves of NdO ₄Ag in 0.6-4.2 K are presented.