Magnetic characteristic evaluation device of magnetic fine particles and magnetic characteristic evaluation method

摘要

PROBLEM TO BE SOLVED: To evaluate magnetical characteristics of a magnetic fine particle with high sensitivity and high accuracy.SOLUTION: A magnetical characteristic evaluation apparatus 1 comprises: a probe device 11 with which a probe formed from a magnetized hard magnetic substance is provided in the distal end thereof; a probe-specimen position adjustment device 12 for adjusting a distance between the probe and a magnetic fine particle; an exciter 13 for mechanically vibrating the probe; an external AC magnetic field generator 14 for applying an external AC magnetic field to one or more magnetic fine particles fixed to a base material, changing a direction or a magnitude of a magnetic moment of the magnetic fine particles and generating a periodically fluctuating magnetic field around the magnetic fine particles; a probe vibration detector 15 for detecting the vibration of the probe including the periodically fluctuating magnetic field as an amplitude modulation signal or a phase modulation signal; a demodulation circuit 16 which inputs a detection signal of the probe vibration detector and generates a signal from the detection signal by demodulating an AC magnetic field generated from the change in the direction or magnitude of the magnetic moment; and a magnetical characteristic evaluation circuit 17 for evaluating magnetical characteristics of the magnetic fine particles on the basis of the signal demodulated by the demodulation circuit.