No abstract

A magnetoplated wire (MPW) is a copper wire whose circumference is plated with a magnetic thin film. The effects of using an MPW are a decrease in the proximity effect, an increase in inductance, and generation of more flux than when copper wire is used. The ratio of the linearity range Lo to the outer coil diameter D of the eddy current displacement sensor is extended by using MPW for the coil. However, the relationship between the Fe film thickness of MPWs and the linearity range characteristic has not been clarified. We measured the output voltage characteristics of MPW coils with Fe film thicknesses of 0.7 μm, 1 μm, and 1.1 μm, and calculated Lo/D ratios. As a result, we found that the Lo/D ratio of an MPW coil with a 1-μm-thick Fe film had a maximum value of 0.66.

We consolidated commercial MgB2 powders by two different shock consolidation methods: the single-stage propellant gun method and the underwater shock consolidation method. The samples prepared had anisotropic resistance–temperature features; the narrowest resistive transition width was observed along the directions of shock loading. In contrast, onset temperatures were independent of the directions and methods. No grain orientation previously observed would have resulted from the consolidation processes with a very short duration of . The samples showed higher diamagnetism than a cold isostatic pressed (CIPed) sample at a low field of 1 Oe. However, their diamagnetism relatively degraded with increasing fields and eventually became much less than even that of the CIPed sample. This is due possibly to thick, much distorted grain boundaries that would have behaved as weak links at high fields.