Analysis of measured transport properties of domain walls in magnetic nanowires and films

Berger, L.

doi:10.1103/physrevb.73.014407

Cited by 26 publications

(16 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In magnetic systems, the DWs themselves can act as scatterers of spinpolarized conduction electrons, and modify the R of the nanowires. This can occur either through direct reflection when DW width ∆ ∼ λ F [16], or by spin-dependent scattering of electrons by the disorder inside the DWs [17,18]. Recently, the fluctuations in R in different forms of nano-magnetic structures have been associated with the motion of DWs [19,20], although the details of the time dependence of R due motion of individual DWs remain unexplored.…”

mentioning

confidence: 99%

“…Two important points are to be noted here: (1) The width of the velocity distribution deceases with increasing H, which can be attributed to the H-induced reduction in the effective propagation barrier that suppresses (lower) part of the barrier energy distribution. (2) Secondly, the typical velocity is about five orders of magnitude lower than thin film-based magnetic nanostrips, which can be understood from the suppression of DW mobility (∼ ∆ 4.4 ) at greatly reduced DW width in nanowires of cylindrical cross section [16].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Tracking Random Walk of Individual Domain Walls in Cylindrical Nanomagnets with Resistance Noise

2010

View full text Add to dashboard Cite

The stochasticity of domain wall (DW) motion in magnetic nanowires has been probed by measuring slow fluctuations, or noise, in electrical resistance at small magnetic fields. By controlled injection of DWs into isolated cylindrical nanowires of nickel, we have been able to track the motion of the DWs between the electrical leads by discrete steps in the resistance. Closer inspection of the time-dependence of noise reveals a diffusive random walk of the DWs with an universal kinetic exponent. Our experiments outline a method with which electrical resistance is able to detect the kinetic state of the DWs inside the nanowires, which can be useful in DW-based memory designs.

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

Tracking Random Walk of Individual Domain Walls in Cylindrical Nanomagnets with Resistance Noise

2010

View full text Add to dashboard Cite

show abstract

“…The dynamics of the motion of domain walls (DWs) in magnetic materials has been extensively explored theoretically [1][2][3] . Depending on the driving force, conventionally magnetic field and, more recently, spin-polarized current [4][5][6][7][8][9][10][11][12][13] , the propagation of DWs changes from a simple translation to more complex precessional modes 14 .…”

mentioning

confidence: 99%

Direct observation of the coherent precession of magnetic domain walls propagating along permalloy nanowires

et al. 2006

View full text Add to dashboard Cite

The dynamics of the motion of domain walls (DWs) in magnetic materials has been extensively explored theoretically 1-3 . Depending on the driving force, conventionally magnetic field and, more recently, spin-polarized current 4-13 , the propagation of DWs changes from a simple translation to more complex precessional modes 14 . Experimentally, indirect evidence of this transition is found from a sudden drop in the wall's velocity [15][16][17][18] , but direct observation of the precessional modes is lacking. Here we show experimentally, using a combination of quasi-static and real-time measurement techniques, that DWs propagate along permalloy nanowires with a periodic variation in the chirality of the walls. The frequency of this oscillation is consistent with a precession of the propagating DW, increasing linearly with field according to the Larmor precession frequency. Current in the nanowire, large enough to significantly influence the DW velocity 18,19 , has little effect on the precession frequency but can be used to adjust the phase of the wall's precession. The highly coherent and reproducible motion of the DW revealed by our studies demonstrates that the DW is a well-defined macroscopic object whose phase is inextricably interlinked to the distance travelled by the DW.With the advent of magnetic nanowires of dimensions comparable to magnetic DW widths, it is possible to imagine that DWs propagating along such wires will exhibit a well-defined precessional mode due to confinement. In contrast, in extended structures, which have been extensively studied in the past, many modes are accessible 1,20 . Permalloy nanowires are attractive because they exhibit large anisotropic magnetoresistance (AMR) so that transverse and vortex walls can be readily detected and identified by resistance measurements. Furthermore, by breaking the onedimensional symmetry of the nanowire with a notch along one of its edges, the chirality of the DW can also be discerned 21 . Here, notched nanowires are used to directly show that the chirality of transverse DWs periodically reverses as the walls propagate in the precessional regime. This precessional motion is also detected in real time using time-resolved resistance measurements, which show that the precessional motion is, surprisingly, highly coherent.A scanning electron microscopy image of a typical permalloy nanowire with two contact lines, labelled A and B, is shown in Fig. 1a. Using a suitable field sequence (see the Methods section), a DW is introduced into section A-B of the nanowire by injecting a voltage pulse into contact line A. A magnetic field, H, is applied along the wire during the voltage pulse injection to assist the subsequent propagation of a DW. A fraction of the injected voltage pulse flows into section A-B, thereby injecting current into the nanowire as the DW propagates along it. The current density that flows into the nanowire scales as ∼0.5 × 10 8 A cm −2 V −1 . Positive current is defined as current flowing from line A to B.The existence of a DW in sectio...

show abstract

“…Classical inductive techniques do not reach the sensitivity allowing us to study the magnetization dynamics in individual magnetic nanostructures, but electrical transport has been shown to reach this goal [4,5]. Thus, the dynamics of the motion of domain walls (DWs) has been recently extensively studied both theoretically [6,7] and experimentally [4,8]. It is typically found that DWs move at typical velocities of tens of metres per second corresponding to typical frequencies below 0.5 GHz [9].…”

Section: Introductionmentioning

confidence: 99%

Electrical detection of internal dynamical properties of domain walls

Sangiao

Viret

2014

Phys. Rev. B

View full text Add to dashboard Cite

We report here on the electrical detection of the ferromagnetic resonance in a notched Py stripe using the spin rectification effect. A lock-in detection technique is used to measure the rectified voltage generated when applying a radio-frequency field. The multiple peaks associated with the presence of a domain wall, observed during field scans, are properly identified with the help of dynamical micromagnetic simulations. It is found that at any frequency below 6 GHz some specific areas of the inhomogeneous magnetization within the domain wall can find a resonant condition and generate a voltage by rectification of the induction currents in the circuit.

show abstract

Analysis of measured transport properties of domain walls in magnetic nanowires and films

Cited by 26 publications

References 42 publications

Tracking Random Walk of Individual Domain Walls in Cylindrical Nanomagnets with Resistance Noise

Tracking Random Walk of Individual Domain Walls in Cylindrical Nanomagnets with Resistance Noise

Direct observation of the coherent precession of magnetic domain walls propagating along permalloy nanowires

Electrical detection of internal dynamical properties of domain walls

Contact Info

Product

Resources

About