| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem that a spatial resolution (measurement resolution) detected is decreased since a generated magnetic flux of an alternating magnetic field applied to a sample is spread to whole magnetic core. SOLUTION: By using an eddy current sensor wherein a magnetic core is made of such a material that a dielectric property becomes remarkable in addition to a magnetic property, at a frequency where an electromagnetic wave inside the magnetic core generated by a combined effect of the magnetic and dielectric properties becomes a stationary wave (the frequency where dimensional resonance is generated), or at frequencies adjacent thereto, the eddy current sensor is operated (a magnetic core is excited) to concentrate a magnetic flux in a crest section of the stationary wave, so that the magnetic field (magnetic flux cross section) is made smaller than a magnetic path cross section of the magnetic core and that the magnetic flux is applied to magnetic core of the eddy current sensor. The eddy current sensor is constructed such that the generated magnetic flux is concentrated to the crest section of the stationary wave when the magnetic core of the eddy current sensor is made of such a material that a dielectric property becomes remarkable in addition to a magnetic property and when the eddy current sensor is operated at the frequency where an electromagnetic wave inside the magnetic core generated by a combined effect of the magnetic and dielectric properties becomes a stationary wave. The material of the magnetic core can be Mn-Zn ferrite. COPYRIGHT: (C)2009,JPO&INPIT
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