Improvement of the Measurement Method of Rock Magnetic Properties Based on the Scanning SQUID Microscope With an In Situ Magnetization/Demagnetization Field

A scanning superconducting quantum interference device microscope with an in situ magnetization/demagnetization field was used to obtain the distribution of the magnetic field and the remanent curves of a wafer sample. It can avoid the position deviation, waste of time, and other interferences caused by the samples' transference between different procedures. The original method of measurement was only functional, with the scanning of samples and detection of preset measured points. The more preset measured point, the finer the sample magnetic characteristic, but the consumption of time and liquid helium will increase. In this paper, we improved the measurement method to reduce the time required for measurement without missing feature points. The sample was scanned first to obtain the contour map of the magnetic field distribution, and then the extreme points in the contour map were selected to be measured for the remanent curves. A wafer geological sample was measured with this improved method and apparent differences in the remanent curves at different measurement points. This improvement of measurement method could reduce the consumption of liquid helium and increase the measurement efficiency by 154%, which is beneficial to the general practical application of this system.