Giant magnetoimpedance effect and domain wall dynamics in Co-rich amorphous microwires

The giant magnetoimpedance (GMI) effect, as well as the magnetic and magneto-optical properties, of Co69.2Fe4.1B11.8Si13.8C1.1 and Fe73.8Cu1Nb3.1B9.1Si13 amorphous microwires is studied. It is observed that the magnetic properties and the GMI effect of the Co-rich microwire can be tuned by heat treatment. A high GMI effect has been observed in as-prepared Co-rich microwires. After appropriate annealing of the Co-rich microwires, fast domain wall propagation and a GMI effect can be simultaneously observed in the same sample, and annealing is seen to affect both the diagonal and off-diagonal GMI components. Using complementary studies of the bulk and surface magnetic properties, an attempt is made to explain the great difference observed in the GMI properties of Co- and Fe-based microwires exhibiting very similar bulk hysteresis loops. (C) 2015 AIP Publishing LLC.