Exchange spring-like inhomogeneous states in a ferromagnetic wire with current

Abstract

Transverse structure of magnetization in a ferromagnetic film induced by magnetic field of electric current has been analyzed. Two steps of arising exchange spring evolution are shown. The first one (weak current) is gradual twisting of magnetization aside from the wire axis. Above some critical current the transient area is compressed and localized near the middle plane. In presence of additional conductive layer the transient structure becomes asymmetric resulting to non-zero lateral component of the net magnetization. It is shown also that the mentioned asymmetry can provide additional displacement of domain walls after the electric current pulses. Keywords: spintronics, domain wall dynamics, exchange spring, ferromagnet.