اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدAll-optical spin switching probability in [Tb/Co] multilayers
102
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Since the first experimental observation of all-optical switching phenomena, intensive research has been focused on finding suitable magnetic systems that can be integrated as storage elements within spintronic devices and whose magnetization can be controlled through ultra-short single laser pulses. We report here atomistic spin simulations of all-optical switching in multilayered structures alternating n monolayers of Tb and m monolayers of Co. By using a two temperature model, we numerically calculate the thermal variation of the magnetization of each sublattice as well as the magnetization dynamics of [Tbn/Com] multilayers upon incidence of a single laser pulse. In particular, the condition to observe thermally-induced magnetization switching is investigated upon varying systematically both the composition of the sample (n,m) and the laser fluence. The samples with one monolayer of Tb as [Tb1/Co2] and [Tb1/Co3] are showing thermally induced magnetization switching above a fluence threshold. The reversal mechanism is mediated by the residual magnetization of the Tb lattice while the Co is fully demagnetized in agreement with the models developed for ferrimagnetic alloys. The switching is however not fully deterministic but the error rate can be tuned by the damping parameter. Increasing the number of monolayers the switching becomes completely stochastic. The intermixing at the Tb/Co interfaces appears to be a promising way to reduce the stochasticity. These results predict for the first time the possibility of TIMS in [Tb/Co] multilayers and suggest the occurrence of sub-picosecond magnetization reversal using single laser pulses.
قيم البحث
اقرأ أيضاً
Amorphous Tb$_{x}$Co$_{100-x}$ magnetic alloys exhibit a list of intriguing properties, such as perpendicular magnetic anisotropy, high magneto-optical activity and magnetization switching using ultrashort optical pulses. Varying the Tb:Co ratio in t
hese alloys allows for tuning properties such as the saturation magnetic moment, coercive field and the performance of the light-induced magnetization switching. In this work, we investigate the magnetic, optical and magneto-optical properties of various Tb$_{x}$Co$_{100-x}$ thin film alloy compositions. We report on the effect the choice of different seeding layers has on the structural and magnetic properties of Tb$_{x}$Co$_{100-x}$ layers. We also demonstrate that for a range of alloys, deposited on fused silica substrates, with Tb content of 24-30 at.$%$, helicity dependent all-optical switching of magnetization can be achieved, albeit in a multi-shot framework. We explain this property to arise from the helicity-dependent laser induced magnetization on the Co sublattice due to the inverse Faraday effect. Our study provides an insight into material aspects for future potential hybrid magneto-plasmonic TbCo-based architectures.
Spin-orbit torque (SOT) magnetization switching of ferromagnets with large perpendicular magnetic anisotropy has a great potential for the next-generation non-volatile magnetoresistive random-access memory (MRAM). It requires a high-performance pure
spin current source with a large spin Hall angle and high electrical conductivity, which can be fabricated by a mass production technique. In this work, we demonstrate ultrahigh efficient and robust SOT magnetization switching in all-sputtered BiSb topological insulator - perpendicularly magnetized Co/Pt multilayers. Despite fabricated by the industry-friendly magnetron sputtering instead of the laboratory molecular beam epitaxy, the topological insulator layer, BiSb, shows a large spin Hall angle of $theta$$_{SH}$ = 12.3 and high electrical conductivity of $sigma$ = 1.5x$10^5$ $Omega^{-1}$m$^{-1}$. Our results demonstrate the mass production capability of BiSb topological insulator for implementation of ultralow power SOT-MRAM and other SOT-based spintronic devices.
All-optical switches are introduced which are based on deoxyribonucleic acid (DNA) in the form of electrospun fibers, where DNA is semi-intercalated with a push-pull, luminescent nonlinear pyrazoline derivative. Optical birefringence is found in the
organic nanofibers, with fully reversible switching controlled through continuous-wave laser irradiation. The photoinduced signal is remarkably large, with birefringence highlighted by optically-driven refractive index anisotropy approaching 0.001. Sub-millisecond characteristic switching times are found. Integrating dye-intercalated DNA complex systems in organic nanofibers, as convenient and efficient approach to template molecular organization and controlling it by external stimuli, might open new routes for realizing optical logic gates, reconfigurable photonic networks and sensors through physically-transient biopolymer components.
We propose a magnetic multilayer layout, in which the indirect exchange coupling (IEC also known as RKKY) can be switched on and off by a slight change in temperature. We demonstrate such on/off IEC switching in a Fe/Cr/FeCr-based system and obtain t
hermal switching widths as small as 10--20~K, essentially in any desired temperature range, including at or just above room temperature. These results add a new dimension of tunable thermal control to IEC in magnetic nanostructures, highly technological in terms of available materials and operating physical regimes.
We employ an atomic spin model and present a systematic investigation from a single spin to a large system of over a million spins. To have an efficient spin switching, the electron initial momentum direction must closely follow the spins orientation
, so the orbital angular momentum is transverse to the spin and consequently the spin-orbit torque lies in the same direction as the spin. The module of the spin-orbit torque is $lambda |{bf S}||{bf r}||{bf P}| sqrt{cos^2alpha+cos^2beta-2cosalpha cosbeta cosgamma} $, where $alpha(beta)$ is the angle between spin {bf S} and position {bf r}(momentum { bf P}) and $gamma$ is the angle between {bf r} and {bf P}. These findings are manifested in a much larger system. The spin response depends on underlying spin structures. A linearly polarized laser pulse creates a dip in a uniform inplane-magnetized thin film, but has little effects on eel and Bloch walls. Both right- and left- circularly polarized light ($sigma^+$ and $sigma^-$) have stronger but different effects in both uniform spin domains and Neel walls. While $sigma^+$ light creates a basin of spins pointing down, $sigma^-$ light creates a mound of spins pointing up. In the vicinity of the structure spins are reversed, similar to the experimental observation. $sigma^+$ light has a dramatic effect, disrupting spins in Bloch walls. By contrast, $sigma^-$ light has a small effect on Bloch walls because $sigma^-$ only switches down spins up and once the spins already point up, there is no major effect.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
