Search

Electric-field (EF) microsensors with high resolution are crucial for the realization of real-time dynamic status monitoring of Ubiquitous Power Internet of Things (UPIoT), which is of great significance for the safe operation of power system and early-stage diagnostics of power equipment. Distortion-free and high-resolution measurement of electric fields is also important in applications such as meteorological monitoring and aerospace launch. Existing electric-field measurement methods are always costly, bulky, and low in resolution. We presented a capacitive EF sensor with small size and high resolution. The presented sensor is based on piezoelectric effect, and a micro cantilever structure is realized using microfabrication. Simulation and experimental results indicate that the presented sensor has a resolution of about 45 V/m and a measurable magnitude of over 1.5 MV/m. Owing to the characteristics of small size, low cost and low power consumption, the EF sensor is suitable for applications of large-scale sensing arrays.

Pb0.6Sr0.4TiO3/La0.7Sr0.3MnO3/La0.7Ca0.3MnO3 (PST/LSMO/LCMO) film is grown on Si substrate by chemical solution deposition method. The film crystallizes perfectly into perovskite phases with a random crystalline orientation. The La0.7Sr0.3MnO3/La0.7Ca0.3MnO3/Si layer exhibits low resistivity and obvious negative magnetoresistivity (MR); the PST/LSMO/LCMO film shows notable magnetocapacitance (MC) above 350 K, from 102.9% to 29.5%. Near room temperature, there is no distinguished magnetoelectric coupling; the MC is 34.3% @ 250 K, 29.5% @ 300 K and 32.8% @ 350 K respectively. The mechanism can be explained in light of the Maxwell–Wagner (MW) model and the enhanced MR origin from the successive mixed manganite phases and spin dependent tunneling across the junctions of PST/LSMO/LCMO. This work provides a new approach for designing and developing novel composites with promising MC.

In response to the challenges of clock speed promotion and power consumption in digital switches, a concept of internal transduction, wherein voltage is transduced to a state internal to the device, which is gated and then transduced back to voltage, was once proposed and highlighted. So far, no embodiments have been demonstrated to perform at a level that would make it competitive with the conventional field-effect transistors moving forward. Here, this natural next step is pursued, and a new method is utilized to transduce an acoustic pulse back to the voltage by magneto piezo-electronic transistors (PETs). These devices provide electric-field control of magnetization in order to change the resistance of the anisotropic magnetic films. Over the course of theoretical and experimental study, the film properties, electric-field manipulation performances, and parameter optimizations are explored and analyzed. The fabricated devices stably achieve a nanosecond switch in a 10-kV/cm electric field with free drive current. In addition, the linear response region is potentially working as a sensor or an actuator. On the basis of this paper, a miniaturized magneto PET is designed and fabricated, in the expectation of speeding up the development of free-current-driven transistors with fast response and low power while scaling down.

Electric-field microelectro-mechanical systems sensors with broad bandwidth and large dynamic range are an enabling technology for real-time monitoring of fast transient overvoltage in the power grid. They significantly alter lightning damage and operation faults and therefore help establish a more secure grid. In this paper, we propose a new method and architecture for electric-field sensing, which overcomes the incompatibilities between electric-field measurements of broad spectrum and large dynamic range. Scientifically, this compound structure with coupled piezoelectric effect and piezoresistive effect transduces electric field changes into resistance alterations via internal pressure. This structure has an hour-glass-shaped cavity, which contains a piezoelectric crystal and leaves the piezoresistive membrane vibrating freely. The newly proposed sensors have a broadened frequency bandwidth of up to 100 kHz and a 15-fold improved sensing magnitude. In addition, this sensor decreases the cost by two orders and reduces energy consumption to 0.018%, which makes them readily implantable into electrical appliances in the power grid.

Current-induced spin-orbit torques (SOTs) in heavy metal/ferromagnet (HM/FM) systems have attracted considerable attention due to the efficient manipulation of the magnetization [1] , To accelerate the application of the SOT spintronic devices into the next generation logic computing and beyond, intensive efforts have been made to explore new materials and mechanisms of SOT. Of particular technological promises are the HMs with a large spin Hall angle θ SH . Pt/Co bilayers/alloys present ultralow resistivity at ~30 μΩ cm [2] , and an enhanced interfacial spin transparency, and thereby strengthen efficiency of the damping-like spin-orbit torque arising from the spin Hall effect in Pt [3] , Researchers concluded that Pt/Co multilayers show great potential for improving the thermal stability and efficient writability. However, it remains undetermined as to how the ferromagnetic thin layer Co modulates the SOTs from HM Pt layers.

High spin-orbit torques (SOTs) generated by topological materials and heavy metals interfaced with a ferromagnetic layer show promise for next generation magnetic memory and logic devices. SOTs generated from the in-plane spin polarization along y-axis originated by the spin Hall and Edelstein effects can switch magnetization collinear with the spin polarization in the absence of external magnetic fields. However, an external magnetic field is required to switch the magnetization along x and z-axes via SOT generated by y-spin polarization. Here, we present that the above limitation can be circumvented by unconventional SOT in magnetron-sputtered thin film MnPd3. In addition to the conventional in-plane anti-damping-like torque due to the y-spin polarization, out-of-plane and in-plane anti-damping-like torques originating from z-spin and x-spin polarizations, respectively have been observed at room temperature. The spin torque efficiency (θ_y) corresponding to the y-spin polarization from MnPd3 thin films grown on thermally oxidized silicon substrate and post annealed at 400 ℃ is 0.34 - 0.44 while the spin conductivity (σ_zx^y) is ~ 5.70 – 7.30× 105 ℏ⁄2e Ω-1m-1. Remarkably, we have demonstrated complete external magnetic field-free switching of perpendicular Co layer via unconventional out-of-plane anti-damping-like torque from z-spin polarization. Based on the density functional theory calculations, we determine that the observed x- and z- spin polarizations with the in-plane charge current are due to the low symmetry of the (114) oriented MnPd3 thin films. Taken together, the new material reported here provides a path to realize a practical spin channel in ultrafast magnetic memory and logic devices.

Topological insulators have recently shown great promise for ultralow-power spin-orbit torque (SOT) devices thanks to their large charge-to-spin conversion efficiency originating from the spin-momentum-locked surface states. Recently, Weyl semimetals emerge as an alternative SOT source with spin-polarized surface as well as bulk states, robustness against magnetic and structural disorder, and higher electrical conductivity for integration in metallic magnetic tunnel junctions. Here, we report that long-range disordered sputtered WTex thin films exhibit local chemical and structural order as those of Weyl semimetal WTe2 and conduction behavior that is consistent with semi-metallic Weyl fermion. We find large charge-to-spin conversion properties in thermally annealed sputtered WTex films that are comparable with those in crystalline WTe2 flakes. Besides, the strength of unidirectional spin Hall magnetoresistance in annealed WTex/Mo/CoFeB heterostructure is 5 to 20 times larger than typical SOT/ferromagnet bilayers reported at room temperature. We further demonstrate room temperature field-free magnetization switching at a current density of 1 – 2 MA/cm2. These large charge-to-spin conversion properties that are robust in the presence of long-range disorder and thermal annealing pave the way for industrial integration of such topological materials. Our results open a new class of sputtered semimetals for memory and computing based on magnetic tunnel junctions as well as broader planar heterostructures consisting of SOT layer/ferromagnet interfaces.

Spin–orbit torque (SOT) magnetoresistive random-access memory (MRAM) devices have been proposed for energy efficient memory and computing applications. New classes of materials such as antiferromagnets, topological insulators, and semimetals can generate spins with unconventional polarization and improve the efficiency of field-free SOT switching. In this work, we report significant changes in SOTs due to a Co thin film inserted in the Pt/Co/Mg/CoFeB heterostructures. Remarkably, the damping-like effective field has been enhanced by 7.4 times after inserting a thin Co layer with weak perpendicular magnetic anisotropy (PMA), while the field-like effective field is reduced to near zero value. Independent characterizations were performed to verify the presence of the changes in SOTs following spin modulation by the Co insertion layer. In addition, we found that the dynamic spin pumping coupling between Pt/Co with weak PMA and the in-plane CoFeB could significantly modulate the effective SOTs in the heterostructure, and this effect is dependent on the thickness of the spacer Mg through long-range spin-wave mediated coupling. Our work has experimentally demonstrated a new avenue to modulate SOTs with physically sputtered metal layers, and this finding is promising to enable flexible and efficient spin polarizations for MRAM devices.

The cathode material LiFePO4/C composites were synthesized by solid-phase method using cheap and extensive FePO4 as iron ingredients and glucose as carbon source. The synthesis conditions were studied by changing the calcined temperatures and the ratio of lithium. The results show that the LiFePO4/C composite synthesized at 600 °C for 10 h exhibits the most homogeneous particle size distribution and excellent electrochemical properties. And it exhibits a specific discharge capacity of 127 mA h/g at 1 C.

Flat and wrinkled La0.7Sr0.3MnO3 (LSMO) thin films were prepared by sol-gel method, respectively, on Si (001) substrates by adjusting heating rate at drying stage. Wrinkled film has larger grains than flat film. Coercive field (about 27 Oe) of wrinkled film is higher than that of flat film, which is much low as around 5 Oe. Compared with flat films, wrinkled films have larger magnetization, higher Curie temperature (334 K) and peak resistivity temperature (243 K), and lower resistivity (0.18 Ohm·cm at 300 K). The introducing of wrinkles is an efficient way to induce compressive stress in sol-gel derived polycrystalline LSMO films and enhance the magnetic and electric properties.

High temperature baking treatment is a method to remove chemical residue on mask before shipping to wafer fab. When developing advanced mask technology, we need to make sure the bake treatment have no side-effect to mask quality. In this investigation, some test has been devised to study the relation between baking process and mask registration, CD movement, repaired point, ion residue and cleaning performance. We also studied how to setup a stable and efficient bake process to make the mask making flow reasonable. The high temperature bake processes was tuned by different temperature, treatment loops setting and was put at different process position to verify the performance. In this paper, OMOG and EAPSM masks were chosen to test by different process condition.

Despite the great promise for very efficient and fast switching of magnetization in embedded memory and computing applications, the performance of spin–orbit torque (SOT) lags behind conventional technologies due to the low spin-Hall conductivity of the spin Hall materials. This work reports an advantageous spin Hall material, periodic [Pt/Co]n multilayer, which combines a low resistivity with a widely tunable spin Hall effect along with magnetization as evidenced with an in-plane CoFeB ferromagnetic detector. Three detection methods have been employed to illustrate the trends of magnetic orientation, interlayer exchange coupling, spin transport, and SOT efficiency as a function of Co thickness, which casts insight into the mechanisms of the SOTs in the [Pt/Co]n multilayer. With the varying Co thickness in the [Pt/Co]n multilayer, it is found that the damping-like torque efficiency is negative and the field-like torque efficiency is 8.2–31.5 times larger. The [Pt/Co]n multilayers have two spin reorientation transition states where the spin Hall angle θSH is maximized with a low resistivity of ∼ 40 μΩ cm, at tCo = 0.507 nm and 0.159 nm. We simulated the magnetization trajectories and time-domain responses of SOT switching with a current pulse and demonstrated a much faster switching in the spin reorientation transition states based on the coupled Landau–Lifshitz–Gilbert equation.

The La 0.7 Ca 0.3 Mn 1−x Fe x O 3 (LCMFO: 0≤x≤0.10) thin films were synthesized by chemical solution deposition process on Si substrates. The structure, magnetic and transport properties have been investigated systematically. With the increase of Fe ion doping concentration, from x=0 to x=0.10, no apparent structural change was observed. While, the magnetization and Curie temperature were reduced dramatically, from 168 emu/cm 3 and 231 K for x=0–18 emu/cm 3 and 81 K for x=0.10, indicating that Fe ion suppressed the double-exchange mechanism and enhanced the anti-ferromagnetic ordering. Meanwhile, the resistance was very sensitive to Fe ion doping and an enhanced magnetoresistance (−94%) was observed in the sample of x=0.05.

SrRuO 3 (SRO) thin films were grown on SiO 2 /Si substrates with different thickness of LaNiO 3 (LNO) seed layers by RF magnetron sputtering. Effects of LNO thickness on the grain orientation, surface morphology, magnetic behavior and electrical transport properties of SRO films were investigated. The orientation of SRO films transformed from (110) pc to (001) pc and the residual stress was released gradually with increasing the thickness (pc refers to the pseudo-cubic unit cell of SrRuO 3 ). SRO films with higher orientation grown on LNO exhibited more flat surface, higher saturation magnetization, and lower coercive field. The magnetic anisotropy was enhanced on thicker LNO due to the different states of residual stress. In addition, the temperature dependence of resistivity was promoted by the microstructural disorder. (110) pc -oriented SRO monolayer electrode and (001) pc -oriented SRO/LNO300 bilayer electrode own low room temperature sheet resistance of 0.38 Ω/□ and 0.26 Ω/□, respectively. The results indicate that the controllable SRO films can be used as not only good bottom electrodes but also promising templates to control the crystallographic orientations of various other perovskite-based functional materials.

As semiconductor devices become extremely integrated and their geometry continues to shrink, even slight critical dimension (CD) move or phase decay during photomask cleaning may have a negative impact on the CD uniformity performance of photomask. In addition, the printing of sub-resolution assist-features (SRAF) on photomask becomes the main limiting factor in using high power and low frequency Mega-sonic cleaning process, therefore, the balance between SRAF damage and clean performance becomes extremely important. In this research, the CD movement both on Chrome layer and MoSi layer and the phase and transmission decay on MoSi layer of advanced PSM photomask induced by Tetra-Methyl-Ammonium-Hydroxide (TMAH) based cleaning process were studied. Meanwhile, the difference between TMAH and SC1 were emphasized. The results showed that TMAH has significant advantage in CD move and phase decay. We also researched the SRAF damage condition after cleaning by the chemical of TMAH with Multi-Beam and Multi-Frequency (MBMF) mode. In addition, we collected different kinds of particles to study the particle remove capability of TMAH under MBMF mode.

OMOG (opaque MoSi on glass) blank is widely used in advanced masks because of its advantage in high resolution and 3D effect1-2. And the manufacture flow is simple compared to phase shift mask. But the repair of this type mask is a challenge. The OMOG material is sensitive to the etching gas thus the etching rate is much higher than PSM. This article presents a problem, the poor edge roughness after repair in OMOG mask, is also related to the high etching rate. The CD (critical dimension) of advanced masks is very small. If there is some distortion in the features’ edge, the AIMS result is easy out of spec. The poor edge roughness we met usually gets poor AIMS result. To find the reason, we checked the manufacture flow and then focused on three steps: repair process, plasma treated process and short clean. Finally we found the plasma treated process was the main reason, and the clean process also contributed to it. Plasma process makes the mask surface oxidization and the oxide layer is high clean durability. The etching rate of oxide is slower than pure OMOG material, and the oxide layer’s uniformity is not good. The two characteristics lead to different etching ratio in the defect area. This is the reason of the poor edge roughness. If the oxide layer is uniform in the defect area, the problem won’t happen. That’s why not all the masks we repaired met the problem. We also found the removal of the oxide layer by clean process could solve this problem. This is an indirect evidence for explaining the reason.

Interface-active particle materials that are able to assemble at the oil/water interface so as to stabilize droplets, are gaining unprecedented interest due to the intriguing applications in catalysis and materials synthesis, etc. In contrast to these potential applications, this kind of materials are still limited and cannot meet some particular demands of practical utilizations such as rationally designed interfacial activity and high stability against concentrated salts. In this contribution, interface-active mesoporous silica nanospheres (MSS@CxZy) are synthesized through simultaneous incorporation of extremely hydrophilic zwitterionic moiety and hydrophobic octyl moiety in the shell. The textural properties of these materials are characterized by transmission electron microscopy (TEM), powder X-ray diffraction (XRD), and nitrogen sorption. The successful decoration of these functionalities in the shell is confirmed by Fourier transform infrared spectra (FT–IR), 13C nuclear cross-polar magnetic resona...

Voltage control of magnetic anisotropy (VCMA) provides an energy-efficient approach to manipulate spintronic devices. Currently, VCMA only shows a weak effect in magnetic tunnel junctions (MTJs) composed of CoFeB/MgO/CoFeB that are the core structure of spintronic memories and logic devices. Multiple approaches have been proposed and studied by researchers to increase the VCMA effect. Here, we demonstrate a large VCMA effect in the CoFeB/MgO/SiO2 double-oxide structure, which can be potentially modified to be compatible with the MTJ cell. The VCMA coefficient as high as 174 fJ/Vm is achieved in this structure at room temperature, with its magnitude comparable to the reported ion-driven VCMA with a high ion-conductive oxide at an elevated temperature. Theoretical analysis indicates that the large VCMA is a magnetoionic effect, which is dominated by ion migration and can be explained by a nanograin cluster model. This double-oxide structure is promising to be extended to an MTJ structure to reduce switching energy in spintronic devices.

Taking advantage of good hermeticity, tiny parasitic capacitance, batch mode fabrication, and compatibility with multiple bonding techniques, the glass-silicon composite substrate manufactured by the glass reflow process has great potential to achieve 3D wafer-level packaging for high performance. However, the difference in etching characteristics between silicon and glass inevitably leads to the formation of the undesired micro-protrusions near the silicon-glass interface when preparing a shallow cavity etched around a few microns in the composite substrate. The micro-protrusions have a comparable height with the depth of the cavity, which increases the risks of damages to sensitive structures and may even trigger electrical breakdown, resulting in thorough device failure. In this paper, we studied the characteristics of the chemical composition and etching mechanisms at the interface carefully and proposed the corresponding optimized solutions that utilized plasma accumulation at the interface to accelerate etching and bridge the gap in etching rates between different chemical compositions. Finally, a smooth transition of 131.1 nm was achieved at the interface, obtaining an ideal etching cavity surface and experimentally demonstrating the feasibility of our proposal. The micromachining solution is beneficial for improving the yield and structural design flexibility of higher performance micro-electromechanical systems (MEMS) devices.

To improve the direct and converse magnetoelectric effects, a magnetic bias field is essential to first excite the magnetization and then determine its sensitivity to a large extent. Based on the minimum energy principle, a ferromagnetic phase model is constructed and amorphous and nanocrystalline alloys are then adopted as example materials to perform numerical calculations to optimize the magnetoelectric effect. Experimental verification of the model showed that the mechanical tensile strain determines the optimum bias in a nonlinear but bijection-type correlation. To improve the magnetoelectric effect in general terms, different ranges of induced strain require a specific optimum bias that can be precisely calculated using the model solution derived in this letter.

The converse magnetoelectric (CME) effect, a coupling effect resulted from compositing piezoelectric phase and piezomagnetic phase, is explored insightfully concerned with applying chip-scale CME composite into extensive electric field measurement. To establish the in-plane longitudinal CME effect, comparable mathematical models elastomechanical tensile model and elastomechanical flexural model are proposed. Grounded on generalized theoretical frameworks, the models utilized some classical magnetoelectric modeling methods. Furthermore, groups of CME composite are taken as examples to simulate and experiment for consistency verification. What highlights in the proposed models is for the purpose of forecasting and evaluating the most favorable composite and structure for CME effect applied in sensing wide range electric field.