Stripped wires: Multifunctional (magnetic and optical) iron–gold barcode nanowires were electrochemically fabricated using nanoporous templates. Structural analysis by TEM elemental line scan and mapping (see images) clearly revealed the well‐separated, bamboo‐like nanostructures composed of Fe and Au strips.

We demonstrate magnetization switching in out-of-plane magnetized Ta\CoFeB\MgO nanowires by current pulse injection along the nanowires, both with and without a constant and uniform magnetic field collinear to the current direction. We deduce that an effective torque arising from spin-orbit effects in the multilayer drives the switching mechanism. While the generation of a component of the magnetization along the current direction is crucial for the switching to occur, we observe that even without a longitudinal field thermally generated magnetization fluctuations can lead to switching. Analysis using a generalized Néel-Brown model enables key parameters of the thermally induced spin-orbit torques switching process to be estimated, such as the attempt frequency and the effective energy barrier.2 Nowadays a large effort is focused on the investigation of novel magnetic materials systems in order to find good candidates for new logic circuits and memory devices. A continuous and growing interest in spin-orbit torque (SOT)-driven magnetization dynamics results from the possibility of using this torque in novel spintronic devices based on ultra-fast current-induced domain wall motion 1 or fast current-induced magnetization switching 2 . The origin of these torques in perpendicularly magnetized multilayers with structural inversion asymmetry (SIA) such as Pt\Co\AlOx 3-6 or Ta\CoFe\MgO 7 seems to be spin-orbit effects generated when an electric current is injected through them. One of the two main effects proposed is the Rashba effect 4,5,8,9 , which generates an in-plane effective magnetic field perpendicular to both the current-flow and the out-ofplane axis. The second one is the spin Hall effect (SHE) 7,[10][11][12][13] , which generates a pure spin-current diffusing across the heavy metal-ferromagnet interface. Such a spin-current has an in-plane spin polarization, which is able to exert a torque on the magnetic texture present in the ferromagnetic layer. However, the debate about the actual origin of the torques is still open. Systems made of Ta\CoFeB\MgO are of particular interest as such a trilayer is already used as a bottom electrode in existing spintronic devices based on CoFeB\MgO\CoFeB magnetic tunnel junctions (MTJs) 14 . The main issue with such devices is the possible damage of the MTJ due to the injection of current across the tunnel barrier, in order to obtain spin-transfer torque (STT)-driven magnetization switching 15 . However, this risk could be mitigated using a three terminal device where switching is driven by SOTs produced by current flowing in plane 16 . In this case only a small read-out current would flow through the tunnel junction -reducing the risk of structural damage to the insulating barrier from high voltages and currents, and making it possible to scale down the cross-section of the MTJs.While the switching of structures using SOTs has been investigated previously 6,7,10 , the switching was only achieved when an additional longitudinal magnetic field was applied, which is cumbersome ...

Magnetic properties and magnetoresistance (MR) in 2D magnetic nanoparticle (NP) arrays are investigated by solving the Landau–Lifshitz–Gilbert equation at T = 0 K. The interparticle interactions induce a decrease in the coercive field and in the MR amplitude compared with the non-interacting case, while in some cases, the variation of the remanent magnetization is found to be non-monotonic when increasing the dipolar strength. For different values of the anisotropy, these variations of the coercive field, the remanent magnetization and the MR ratio are reproduced and exhibit a scaling on the dipolar/anisotropy ratio. These results suggest that the magnetic properties of the assemblies can be described by an individual or collective behaviour depending on the balance between the magnetic anisotropy and the dipolar interactions. In the case of strongly interacting NPs, the corresponding configurations of the magnetic moments at the remanent state reveal the formation of a ferromagnetic order at moderate dipolar strength (increase in the remanent magnetization) while small ferromagnetic domains/chains coupled antiferromagnetically are obtained in the case of strongly interacting NPs (decrease in the remanent magnetization). Such domains lead to a reduction in the MR amplitude and to a deviation from the m2-law in the resistance-magnetic field [R(H)] characteristic of the non-interacting case.

Gestreifte Drähte: Multifunktionelle (magnetisch und optisch) Eisen‐Gold‐Barcode‐Nanodrähte wurden elektrochemisch mithilfe nanoporöser Template hergestellt. Die Strukturanalyse durch TEM‐Elementlinien‐Scan und ‐Kartieren (siehe Bilder) belegt eindeutig die gut getrennten, bambusartigen Nanostrukturen aus Fe‐ und Au‐Streifen.

The Fourier analysis of magnetic force microscopy imaging J. Appl. Phys. 112, 063913 (2012) The magnetic Y-branch nanojunction: Domain-wall structure and magneto-resistance Appl. Phys. Lett. 101, 102403 (2012) Fast domain wall dynamics in MnAs/GaAs films Appl. Phys. Lett. 101, 072408 (2012) Magnetic domain wall induced, localized nanowire reversal