Re-entrant flux reversal in 80Ni-4.2Mo-Fe permalloy wires

The re-entrant flux reversal effect was observed in commercially produced wire (44 and 117 mu m in diameter) that had been made with Carpenter HyMu ''80''(R) alloy (Ni80Mo4.2Febal permalloy). The critical field (H-j) for the flux jump decreased (to 0.2 Oe) with increased annealing temperature (e.g., 700 degrees C). However, after annealing at higher temperatures (e.g., 900 degrees C) the re-entrant effect disappears. The factors that affect re-entrant flux reversal in permalloy wire, such as wire diameter, length, heat treatment, and magnetic field, were investigated. The signals generated from amorphous and permalloy wires were also compared. (C) 1997 American Institute of Physics.