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Spin–orbit coupling (SOC), the interaction between spin and orbital angular momentum of electrons, is imperative to control magnetic properties of nonmagnet (NM)/ferromagnet (FM) heterostructures and design energy‐efficient and faster spin‐based devices. Here, femtosecond pulsed laser‐induced time‐resolved magneto‐optical Kerr effect magnetometry is employed to investigate magnetization dynamics in different NM/Co20Fe60B20 heterostructures, where the NM layer varies as Cu, Ta, W, Pt, Ta/Ru/Ta, and Si/SiO2 (no underlayer) that differ in SOC strength. It is observed that there is a systematic variation in ultrafast demagnetization time (τm), fast remagnetization time (τr), and Gilbert damping parameter (α) with the SOC strength of the underlayer and an inverse relationship between α and τm, τr is established due to the dominant contribution of spin current transport in ultrafast demagnetization and fast remagnetization processes. The spin pumping formalism estimates the effective spin‐mixing conductance (Geff) for different interfaces, which signifies that the high SOC strength of underlayers results in high Geff indicating more efficient transport of spin current through it. This study suggests that the SOC strength of the NM underlayer plays a significant role in controlling the ultrafast demagnetization process through interfacial spin current transport in a NM/FM heterostructure which can be beneficial for the development of ultrafast spintronics devices. [ABSTRACT FROM AUTHOR]

We have monitored a magnetization process in a ferromagnetic disk by measuring a bend resistance of semiconductor two-dimensional electron gas (2DEG) lying beneath the disk. Annihilation and nucleation of a vortex in the ferromagnetic disk are clearly seen in the trace of the bend resistance as a function of in-plane magnetic field. The large change in the signal is well reproduced by a simulation based on a semiclassical billiard model. [ABSTRACT FROM AUTHOR]

Focuses on a study which investigated the magnetostatic effect of the micron-size ferromagnetic particle array on a two-dimensional superconductor. Details of experimental set-up; Comparison of bare niobium (Nb) film with that of Nb film with ferromagnetic particles; Cause of the difference in the magnetization curves.

Abstract: The transport properties of diffusive spin currents have been investigated in lateral ferromagnetic/nonmagnetic metal hybrid structures. The spin diffusion processes were found strongly dependent on the magnitude of the spin resistances of connected materials. The efficient spin injection and detection are accomplished by optimizing the junction structures on the basis of the spin resistance circuitry. The magnetization switching of a nano-scale ferromagnetic particle and also room temperature spin Hall effect measurements were demonstrated by using an efficient pure-spin-current injection. [ABSTRACT FROM AUTHOR]

We microscopically demonstrate that the magnetic domain is controllably nucleated and erased in the uniformly magnetized wire using a current pulse in small magnetic fields. Lorentz microscopy is performed in Permalloy nanowires with in-plane anisotropy. The stochastic nature of the magnetization reversal due to spin wave and thermal excitations in the absence of magnetic field completely disappears and turns into deterministic in the presence of small magnetic field, which enables the magnetization reversal control. We interpret that the phenomena are associated with Zeeman energy stabilization. [ABSTRACT FROM AUTHOR]

The authors have investigated dynamics of paired domain walls in a ferromagnetic ring circuit, driven by a variable pulsed magnetic field. The magnetic reversal accompanied by the propagations of the domain walls depends not only on the amplitude but also on the rise time of the applied pulsed magnetic field. The threshold of the rise time is found comparable to the propagation time of a domain wall along a half-path of the ring. This finding may be useful for the high speed operation of the magnetic logic devices based on the domain wall motion. [ABSTRACT FROM AUTHOR]

Magnetically coupled domain wall pinning has been investigated by means of an attached pair of ferromagnetic wires. The magnetic configuration of the paired wires (parallel or antiparallel) can be controlled by applying an external magnetic field along the wires. The strength of the pinning due to the magnetic interaction between the domain wall and the paired wires shows a significant difference between the parallel and antiparallel configurations, which is well reproduced by a micromagnetics simulation. [ABSTRACT FROM AUTHOR]

We have developed a method of measuring magnetization process in a ferromagnetic ring by analyzing a characteristic response of a semiconductor two-dimensional electron gas (2DEG) lying beneath the ring. A 2DEG microcross structure is formed underneath a ferromagnetic ring to detect the position of paired domain walls of the onion state. The variation of the bend resistance due to the rotation of the paired domain walls is quantitatively reproduced by a semiclassical billiard model. [ABSTRACT FROM AUTHOR]

A key mechanism of the current-induced magnetization dynamics is the spin torque from a spin polarized current (spin current), which couples to spatial gradient of magnetization. Recently, it was pointed out that a large spin current applied to a uniform ferromagnet leads to a spin-wave instability. In this paper, we show that such instability is absent in a state containing a domain wall. This may indicate that nucleation of magnetic domains occurs above a certain critical spin current. This scenario is supported by an explicit energy comparison between the uniformly magnetized state and the domain-wall state under spin current. [ABSTRACT FROM AUTHOR]

Focuses on submicron cobalt (Co) wires which were prepared to investigate the magnetoresistance effect in association with the domain wall formation. Information on ferromagnetic Co wires; Discussion on Co paired disks.

Focuses on arrays of submicron cobalt (Co) rectangular dots with the different aspect ratio and those of Co rectangular antidots which were prepared by a high resolution lithography technique. Magnetic properties of submicron ferromagnetic dots and antidots; Fabrication of arrays of Co rectangular particles; Information on the atomic and magnetic force microscope images for arrays of both dots and antidots.

Ultrafast spin dynamics in ferromagnetic nanodot arrays with dot diameter 100 nm and thickness 20 nm arranged in honeycomb and octagonal lattice symmetries are studied to explore the tunability of the collective magnetization dynamics. By varying the inter-dot separation between 30 nm and 300 nm drastic variation in the precessional dynamics from strongly collective to completely isolated regime has been observed by using all-optical time-resolved magneto-optical Kerr microscope. Micromagnetic simulation is exploited to gain insights about the resonant mode profiles and magnetic coupling between the nanodots. A significant spectral and spatial variation in the resonant mode with increasing dipolar interaction is demonstrated with increasing inter-dot separation. The spins driven by effective field inside single nanodots are prone to precess independently, generating two self-standing centre and edge modes in the array that are influenced by the relative orientation between the inter-dot coupling direction and bias magnetic field. The anisotropic behavior of dipolar field is rigorously investigated here. Splitting of the centre mode in case of octagonal lattice is experimentally observed here as a consequence of the anisotropic dipolar field between the nanodot pairs coupled horizontally and vertically, which is not found in the honeycomb lattice. In addition, proper understanding of the modification of dynamic mode profile by neighboring dipolar interaction built up here, is imperative for further control of the dynamic dipolar interaction and the corresponding collective excitation in magnonic crystals. The usage of nanodot lattices with complex basis structures can be advantageous for the designing of high density magnetic recording media, spin-wave filter and logic devices. [ABSTRACT FROM AUTHOR]

Lateral spin devices are an important concept in nowadays all-metallic spintronic devices. One of the key problems is to obtain large spin injection and detection efficiency. Several concepts has been envisaged, such as to use half-metallic ferromagnetic electrodes or spin-polarized interface barriers. Within this work, we address the optimization of spin devices (namely optimization of spin current density, spin current and spin accumulation) based on adjustment of the geometry (dimensions) of the lateral device, material selection of spin conductors, jointly with optimization of the interface resistance. [ABSTRACT FROM AUTHOR]

The conductance in ferromagnetic Ni nano-wire is quantized in units of 2e2/h in the absence of magnetic field, while the units switch to e2/h in the magnetic field. The fractional units of 0.7e2/h and 1.4e2/h with and without magnetic field appear under the application of high bias-voltage. The spin polarization and bias-voltage play an important role in the electric conduction. [Copyright &y& Elsevier]