抄録
The remanence of a μT level magnetic flux density remaining in volcanic rock and lava is one of important measurement data in geophysics fields. Generally magnetic fields far from a sample with remanence are measured by SQUID(Superconducting QUantum Interference Device)gradiometer inside a shielding room and presume the remanence irrespective of a size and form of sample. However, it is difficult to measure a magnetic field on site or under additional measurement environment, such as heating and demagnetizing. We proposed the methodology without shield system by measuring magnetic fields inside a hole in which the sample is rotated. The basic methodology to measure two components of remanence in a single hole was reported previously. The paper proposes the method to measure three components of remanence by using a needle GMR(Giant Magneto Resistance) sensor.
