MAGNETIC DOMAIN NUCLEATION AND PROPAGATION IN FINE WIRES

The effect of material composition and structure on the magnetic domain nucleation field (Hn) and the domain wall propagation field (H p) in fine cold-drawn Permalloy wires is reported. Binary Ni/Fe wires (Fe>20%) were reentrant (Hn>Hp) when cold drawn to less than 250 μm diam. Alloying additions inhibited stress recovery during drawing and annealing and thereby increased and stabilized Hn. Variations in Hn along the wire length correlated with defects in the wire surface. Sputter coating the wire improved the surface condition and reduced variations in Hn. A magnetostrictive model of re-entrancy is proposed and discussed. © 1969 The American Institute of Physics.