Magnetic properties and microstructure of V/sub 3/Si multifilamentary superconductors

Magnetic properties, in correlation with cross-sectional microstructures, were studied in order to check the potentiality of V/sub 3/Si multifilamentary superconductors for AC use. Irregularity of V filaments brings about the bridging between filaments during heat treatments. The effective filament diameter D/sub eff/ of 2.3 /spl mu/m is, however, comparable to that of bronze processed Nb/sub 3/Sn conductors. At long heat treatments, the V/sub 5/Si/sub 3/ layer initially forming around V/sub 3/Si filaments disappears, and then proximity coupling occurs additionally to the bridging. The proximity coupling causes the two peaks to appear in the magnetization curves and D/sub eff/ to increase at low fields. The existence of V/sub 5/Si/sub 3/ is quite effective in reducing D/sub eff/ and hence hysteresis loss.<<ETX>>