Direct Observation of Domain-Wall Configurations Transformed by Spin Currents

Abstract

Direct observations of current-induced domain-wall propagation by spin-polarized scanning electron microscopy are reported. Current pulses move head-to-head as well as tail-to-tail walls in submicrometer Fe20Ni80 wires in the direction of the electron flow, and a decay of the wall velocity with the number of injected current pulses is observed. High-resolution images of the domain walls reveal that the wall spin structure is transformed from a vortex to a transverse configuration with subsequent pulse injections. The change in spin structure is directly correlated with the decay of the velocity.

High domain wall velocities in in-plane magnetized (Ga,Mn)(As,P) layers

“…However, the observed maximum velocities are underestimated by a factor of about 1.5, and the velocity plateaus are unexpected within this model. As evidenced repeatedly in both simulations 3 and experiments 30 , an abrupt change in velocity often results from a modification of the nature of the DW. A modification of the domain profile can indeed be seen on the domain images of samples A3 and A4 (Fig.…”

Current-driven magnetic domain wall motion and its real-time detection

“…The underlying mechanism of CIDWM was first investigated. The microscopic structure of a DW was observed by using advanced imaging techniques, [21][22][23] from which it was found that there are four types of DWs: transverse and vortex DWs with clockwise and counterclockwise spin rotation. It was revealed that among the DW types, the vortex DW is more mobile than the transverse one.…”

“…It was revealed that among the DW types, the vortex DW is more mobile than the transverse one. 22) Issues related to non-adiabatic STT were also actively discussed. At the time, most of the CIDWM results were assumed to be predominantly governed by the non-adiabatic STT because the current densities required to move the DW were much smaller than the threshold value predicted theoretically on the basis of intrinsic pinning.…”

Critical nucleation size of vortex core for domain wall transformation in soft magnetic thin film nanostrips

“…DOI: 10.1103/PhysRevB.80.012402 PACS number͑s͒: 75.60.Ch, 75.70.Kw, 75.75.ϩa Numerous recent studies in the fields of nanomagnetism and magnetization ͑M͒ dynamics have focused on magnetic field and/or current driven dynamic motions of domain walls ͑DWs͒ in patterned magnetic thin film nanostrips, 1-7 owing to the potential applications to solid-state data storage and logic devices. [8][9][10][11][12][13][14] One of the most fundamental issues in this field is the underlying physics of the breakdown of DW velocity and oscillatory DW motions under magnetic fields exceeding a threshold field known as the Walker field, H w . This question has been approached by Walker, 15 Thiaville et al, 16 and Nakatani et al 3 within the context of one-dimensional ͑1D͒ models.…”

“…[8][9][10][11][12][13][14] One of the most fundamental issues in this field is the underlying physics of the breakdown of DW velocity and oscillatory DW motions under magnetic fields exceeding a threshold field known as the Walker field, H w . This question has been approached by Walker, 15 Thiaville et al, 16 and Nakatani et al 3 within the context of one-dimensional ͑1D͒ models.…”