High-field domain wall propagation velocity in magnetic nanowires

Physics Department, The Hong Kong University of Science and Technology - Clear Water Bay, Hong Kong SAR, China

Corresponding author: lujie@ust.hk

Received: 8 March 2009
Accepted: 29 May 2009

Abstract

A theory of field-induced domain wall (DW) propagation is developed. The theory not only explains why a DW in a defect-free nanowire must propagate at a finite velocity, but also provides a proper definition of DW propagation velocity. This definition, valid for an arbitrary DW structure, allows one to compute the instantaneous DW velocity in a meaningful way even when the DW is not moving as a rigid body. A new velocity-field formula beyond the Walker breakdown field, which is in excellent agreement with both experiments and numerical simulations, is derived.