The electro-optically interrogated surface plasmons device consists of a heterolayer structure formed by Au, graphene, and an ion-gel layer. Tuning of the reflectance was achieved by applying an external electric field across the heterolayer.
The prospect of all electrically controlled writing of ferromagnetic bits is highly desirable for developing scalable and energy-efficient spintronics devices. In the present work, we perform micromagnetic simulations to investigate the electric field-induced strain mediated magnetization switching in artificial spin ice (ASI) based multiferroic system, which is proposed to have a significant decrease in Joule heating losses compared to electric current based methods. As the piezo electric strain-based system cannot switch the magnetization by $180^\circ$ in ferromagnets, we propose an ASI multiferroic system consisting of the peanut-shaped nanomagnets on ferroelectric substrate with the angle between the easy axis and hard axis of magnetization less than $90^\circ$. Here the piezoelectric strain-controlled magnetization switching has been studied by applying the electric field pulse at different angles with respect to the axes of the system. Remarkably, magnetization switches by $180^\circ$ only if the external electric field pulse is applied at some specific angles, close to the anisotropy axis of the system ( $\sim 30^\circ - 60^\circ$). Our detailed analysis of the demagnetization energy variation reveals that the energy barrier becomes antisymmetric in such cases, facilitating the complete magnetization reversal. Moreover, we have also proposed a possible magnetization reversal mechanism with two sequential electric field pulses of relatively smaller magnitude. We believe that the present work could pave the way for future ASI-based multiferroic system for scalable magnetic field-free low power spintronics devices.
Graphene has gained lot of attention due to its exception properties of high electron mobility, electric current carrying capacity, high optically transparency and considered as an excellent candidate for next-generation optical and electrical devices. The interface between graphene and silicon has been shown to form a Schottky barrier, which exhibits rectifying properties - allowing current to flow in one direction, enabling its use as an electrical diode. Furthermore, graphene's optical transparency, along with its strong optoelectronic response, allows the generation of photocurrent by the graphene-silicon diode when absorbing light, making it suitable for use as a high-sensitive photodetector with higher responsiveness and improved light-to-dark current ratio.
The prospect of electrically controlled writing of ferromagnetic bits is highly desirable for developing scalable and energy-efficient spintronics devices. In this direction, various efforts have been made to achieve electrically controlled magnetization switching utilizing an artificial multiferroic system. To date, the magnetization switching has been realized in a diverse nanopatterned magnetic system. However, the demonstration of electric field-induced strain-controlled magnetization switching in artificial spin ice (ASI) coupled with a piezoelectric material is still unexplored. In the present work, we perform micromagnetic simulations to investigate the electric field-induced strain-mediated magnetization switching in an ASI based multiferroic system. Here, the piezoelectric strain-controlled magnetization switching has been studied by applying the electric-field pulse at different angles with respect to the axes of the system. Remarkably, magnetization switches by 180° only if the external electric-field pulse is applied at some specific angles, close to the anisotropy axis of the system (≈30°–60°). Our detailed analysis of the demagnetization energy variation reveals that the energy barrier becomes antisymmetric in such cases, facilitating complete magnetization reversal. Moreover, we have also proposed a possible magnetization reversal mechanism with two sequential electric-field pulses of a relatively smaller magnitude. We believe that the present work could pave the way for a future ASI-based multiferroic system for scalable magnetic field-free low power spintronics devices.
Tungsten is the first choice for Plasma Facing Components because of their favorable properties such as high melting point, high threshold energy, low threshold shock resistance, resistance to form co-deposits with tritium. However, He irradiation defects on W may lead to Deuterium-Tritium reaction failure in the magnetic fusion reactors. In this work, we investigate the effects of helium ions flux, created by a UNU/ICPT dense plasma focus (DPF) device, on a PLANSEE double forged W and nanostructurized tungsten (nano-W). For the poly-W samples, SEM images showed the extent of surface and subsurface of W damage due to helium flux irradiation. The increase in numbers of hydrogen shots results in micro-cracks and blisters on the sample surface followed by re-solidification of the sputtered and melted surface. Nanostructurization of W has been achieved by exposing the W samples to Argon plasma in the UNU/ICPT DPF device to improve the performance. This results in well-distributed highly dense nanoparticles of ∼ 20–50 nm size. He ions exposed nano-W samples showed micro-cracks and nanopores, instead of blisters and holes. Back scattered imaging of the nano-W provides an indication of He bubbles trapping in the grain boundaries. The nano-W with improved surface and structural properties can be good candidate for plasma-facing materials.
Flexible multiferroic composite with enhanced dielectric property is a potential candidate for future memory devices. Here, 0–3 type of artificial multiferroic was developed to enhance the dielectric property of the multiferroic composite. As the loading of the magnetic nanoparticles in the PVDF matrix increases from 10 wt% to 40 wt% the electroactive phase of the composite increases probed by dielectric measurement. The increase in the loading of magnetic nanoparticles inside the PVDF matrix from 10 to 40 wt% also control the dielectric losses of the samples. The vibrating sample magnetometer measurement was performed for the composite films with varying composition and found that the magnetic moment is increased linearly with the loading of magnetic nanoparticles. Our 0–3 type multiferroic composite device is nonvolatile in nature which can form the basis for future nonvolatile magnetic memory devices. To further improve the dielectric and magnetoelectric property of the multiferroic composite samples, different wt % of NiFe 2 O 4 NPs was exposed by dense plasma focus device in the oxygen environment. After oxygen plasma exposure the electrical and magnetic properties measurement performed using I-V and magnetoelectric measurement setup respectively. The enhancement in the magnetoelectric properties has been observed after the plasma treatment. Thus, it suggests that plasma modification could be a promising approach to enhance the magnetoelectric coupling for future magnetoelectric devices.
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