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Lithium phosphorus oxynitride (LiPON) film with high ionic conductivity, low electronic conductivity and high transparency in UV-VIS range offers the possible applications as electrolyte for optical devices, e.g. electrochromic device. In this work, the optical properties of LiPON are investigated by means of variable-angle spectroscopic ellipsometry (VASE) and optical transmission spectra. LiPON thin films with composition of Li3.13PO1.69N1.39 and ionic conductivity of 4.9 × 10−6 S cm−1 at room temperature were prepared by RF magnetron sputtering. Optical constants have been derived on multiple samples with film thickness from 400 to 2000 nm in the energy range of 0.58-5.5 eV. The optical bandgap ( Eg) of LiPON film is shown to be 3.07 eV by a Tauc plot. It is found that when E < Eg the Urbach exponential decay of absorption is observed. The Urbach tail width at room temperature is estimated to be 0.361 eV for the LiPON film. [ABSTRACT FROM AUTHOR]

Lithium silicon phosphorus oxynitride (LiSiPON) thin films with different compositions have been prepared by RF magnetron sputtering in N2 by using three targets xLi2SiO3 · (1 − x) Li3PO4 with x = 0.1, 0.3, and 0.5. Compared with LiPON, the electrical properties of LiSiPON have been improved by introducing silicon. LiSiPON films deposited from the target 0.5Li2SiO3 · 0.5Li3PO4 yield the highest ionic conductivity of up to 9.7 × 10−6 S cm−1 with an activation energy of only 0.41 eV. The main mechanism for increasing ionic conductivity is the enhancement of carrier mobility. By DC polarization measurements the electronic partial conductivity was found at least seven orders of magnitude smaller than the ionic conductivity. Linear voltammetry results showed that the LiSiPON films are electrochemically stable in contact with stainless steel in the voltage range of 0-6 V. The substitution of silicon for phosphorus in the film evidenced from X-ray photoelectron spectroscopy analysis indicated silicon in the film will create more abundant cross-linking structures Si-O-P and (P, Si)-N < (P, Si), hence created more Li+ conducting paths which favored the higher mobility of lithium ions and larger ionic conductivity. The optical bandgap was found to decrease with increasing silicon content. We demonstrate that the prepared LiSiPON films with their larger ionic conductivity and low electronic conductivity may serve as an alternative to LiPON for applications in high energy density and high voltage lithium batteries. [ABSTRACT FROM AUTHOR]

Transparent amorphous lithium phosphorus oxynitride (LiPON) thin films with different thickness have been prepared by RF magnetron sputtering at a growth rate of 14 nm/min. The mean ionic conductivity of as-deposited LiPON films determined by impedance spectroscopy was 4.9 μS/cm at 22 °C with the activation energy of 0.55 eV. The electronic partial conductivity was measured to be 1.6 × 10 − 6 μS/cm by recording the current–time curves at a constant voltage. The optical transmission of LiPON films were measured by UV–Vis/IR spectroscopy. The prepared LiPON films on silica glass substrate showed transmission higher than 80% in the visible light range. The complex refractive index and bandgap (~ 2.94 eV) were estimated by fitting the transmission data with the Tauc–Lorentz dielectric function model. The local structure of the film was investigated by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Both methods confirmed the incorporation of nitrogen in the matrix. Nitrogen is present in two different chemical environments, corresponding to P − N < P P and P N P. Inductively coupled plasma-optical emission spectrometry (ICP-OES) and Rutherford backscattering spectrometry (RBS) measurements showed that the composition of the LiPON film was Li 3.13 PO 1.69 N 1.39 . The high nitrogen content and low oxygen content appears to be responsible for the specific electrical and optical properties of the LiPON films. [ABSTRACT FROM AUTHOR]

Comparing with BiOX (X = Cl, Br, I), Bi x O y X z as the newest bismuth-based photocatalysts have more appropriate conduction band position. And so, they can be used to active molecular oxygen. In this paper, Bi 5 O 7 Br, a new Bi x O y X z semiconductor photocatalyst was firstly synthesized by via hydromel method. It was characterized by X-ray diffraction (XRD), UV–visible diffused reflectance spectra (DRS), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and the corresponding selected-area electron diffraction (SAED) pattern. It can be found that the crystal structure and morphology are same with Bi 5 O 7 I. The size of a single rod is about 2 μm in width and 50 μm in length. As-synthesized Bi 5 O 7 Br can effectively activate molecular oxygen to generate superoxide radical (O 2 •− ) and hydroxyl radical (•OH) under UV–vis light irradiation. And it also showed high photocatalytic activity than BiOBr for the degradation of dyes. Thus, it can be seen, the appearance of Bi 5 O 7 Br photocatalysis enriched the bismuth-rich strategy of Bi-O-X photocatalysts. [ABSTRACT FROM AUTHOR]

Highlights: [•] Hydrothermal pH value cannot change the dominant exposed facet of BiOBr nanosheets. [•] The UV and visible light (λ >500nm) photocatalytic activity of BiOBr increased with are hydrothermal pH value increasing. [•] The photocatalytic activity order of BiOBr is mainly attributed to the size rather than the facet effect. [Copyright &y& Elsevier]

• Antiferromagnetic (AFM) spintronics are the emergent research field in spintronics due to the superior properties of AFM materials in comparison to ferromagnetic (FM) materials for the applications in magnetic memory devices. So far how to effective electrical writing and reading of AFM states are the main focus in this field. • Here we propose and investigate the pure voltage controlled magnetic anisotropy (VCMA) effect in two representative AFM materials L 1 0 -MnPt and MnPd by using first-principles calculations. Our results indicate that for MnPt, at certain thickness the moderate electric field is able to switch its Néel vector between in-plane [1 0 0] and [1 1 0] direction. For MnPd, the VCMA coefficient is estimated to be around 20 fJ/V/m. • This work will attract broad research interest in voltage controlled effect in AFM films and open new perspective for effective writing and reading of the AFM state. The efficient electrical control of the magnetic states of antiferromagnets is one of the main focus in antiferromagnetic spintronics. In this work, the voltage-controlled magnetic anisotropy (VCMA) effect in two representative antiferromagnets L 1 0 -type MnPt and MnPd thin films has been investigated by employing first-principles calculations. Our results indicate that both of the MnPt and MnPd films show in-plane magnetic anisotropy and the magnetic easy axis points either along [1 0 0] or [1 1 0] direction depending on the film thickness. The applied electric field in the range of −0.3 V/Å and + 0.3 V/Å (vacuum as dielectric) leads to the change of magnetocrystalline anisotropy of both films at the order of tens of μJ/m2. Especially, for MnPt film with thickness of two unit cells on Pt(0 0 1), it shows that the moderate electric field is able to switch the in-plane magnetic easy axis between [1 0 0] and [1 1 0] directions. For MnPd thin films, the VCMA effect shows generally linear dependence on the electric field and the VCMA coefficients are estimated in the range of 2.7 to 22.6 fJ/V/m. Our calculation results may stimulate future investigations on the VCMA effect of metallic antiferromagnetic films and pave the possible applications in memory device. [ABSTRACT FROM AUTHOR]

Multiferroic tunnel junctions (MFTJs) comprised of magnetic electrodes and a ferroelectric tunnel barrier have been emerging as promising candidates for nonvolatile memory applications. The recently discovered above room-temperature van der Waals (vdW) ferromagnet Fe3GaTe2 and ferroelectric α-In2Se3 provides possibilities for constructing room-temperature vdW MFTJs. In this work, by using first-principles calculations, we investigate the spin-dependent transport in vdW MFTJs with structure of Fe3GaTe2/bilayer α-In2Se3/Fe3GaTe2. We predict a giant tunneling magnetoresistance (TMR) high up to 10 000% by switching the magnetic alignments of Fe3GaTe2 and tunneling electroresistance (TER) exceeding 300% by controlling the ferroelectric configurations of bilayer α-In2Se3 in the proposed MFTJs. Furthermore, by introducing interface asymmetry and inserting monolayer of h-BN on one interface, the TMR and TER ratios of the MFTJs can be substantially enhanced. In consequence, the multi-level resistance states can be achieved by applying magnetic and electric field in asymmetric MFTJs. Our results highlight full vdW MFTJs for their potential applications in spintronic devices, particularly in the field of multilevel nonvolatile memories. [ABSTRACT FROM AUTHOR]

• The T-type magnetic configuration with interlayer exchange coupling. • Pt(5)/Co(t, in plane)/Ta(0.6)/CoTb(6, out-of-plane)/Ta(2 nm) heterostructure. • Modulation of switching current density in T-type magnetic structure by magnetic anisotropy. • The magnetic anisotropy of the Co layer and the domain wall motion of the CoTb layer can be modulated. We investigate magnetic field driven domain wall motion and spin-orbit torque (SOT) induced perpendicular magnetization switching of the ferrimagnetic layer in a T-type magnetic heterojunction with the structure of Pt/Co/Ta/Co 81 Tb 19 /Ta, where the bottom Co layer has in-plane magnetic anisotropy and the top Co 81 Tb 19 layer has perpendicular magnetic anisotropy. It is found that the magnetic field driven domain wall motion and the depinning field of the Co 81 Tb 19 layer can be effectively tuned by the thickness of the Co layer (t Co). Meanwhile, SOT-induced perpendicular magnetization switching of the Co 81 Tb 19 layer is observed, and the critical switching current density first decreases and then increases with increasing the thickness of the Co layer. A lower critical switching current density was obtained at the optimized thickness (t Co = 1.2 nm), resulting in a 37% reduction in critical switching current density. Meanwhile, the research reveals a strong correlation between critical switching current density and magnetic anisotropy field, indicating that tuning the magnetic anisotropy is an efficient way to modulate the switching current density in a T-type magnetic structure. These results provide a new perspective on SOT manipulation and will be useful for the design of SOT-based devices. [ABSTRACT FROM AUTHOR]

Lithium phosphorus sulfuric oxide nitride (LiPSON) prepared by radio frequency sputtering is investigated as a transparent solid lithium‐ion conductor for use in all‐solid‐state electrochromic (EC) devices. The LiPSON layers are characterized by X‐ray photoelectron spectroscopy (XPS) and their electrical characteristics are studied by temperature‐dependent impedance spectroscopy. Half‐cells of LiPSON deposited on tungsten oxide (WOx) in contact with 1 m LiClO4 in propylene carbonate are studied by electrochemical impedance spectroscopy (EIS) and spectroelectrochemical measurements by cyclic voltammetry and chronoamperometry. A significant influence of LiPSON deposition conditions on the EC characteristics of WOx is observed in the achievable transparency change, as well as the color impression in the bleached and colored state. Formation of a solid−electrolyte interface (SEI) is indicated that leads to poor EC performance with long switching times of 20−60 min. Appropriate deposition conditions for LiPSON are established that maintain a good EC activity of WOx. An all‐solid‐state EC device is assembled of WOx/LiPSON with vanadium titanium oxide as counter electrode and aluminum‐doped zinc oxide as back contact. Temperature‐dependent EIS and spectroelectrochemical measurements show that in such an all‐solid‐state stack, the detrimental contact resistance could be avoided and switching times of less than 60 s are achieved. [ABSTRACT FROM AUTHOR]

The exchange bias effect resulting from antiferromagnetic materials plays a crucial role in spintronics devices. This effect can effectively fix the orientation of magnetization at the interface and is essential for magnetization control and switching behavior. Noncollinear antiferromagnetic materials have recently received much attention due to their novel physical properties. Here, we investigate the exchange bias effect in the noncollinear antiferromagnetic Mn 3 Sn/Py bilayers. It indicates the exchange bias and blocking temperature is directly related to the surface roughness and thickness of the noncollinear antiferromagnetic layer. By optimizing the thickness and deposition temperature, we achieve an exchange bias of 538 Oe at 5 K and a blocking temperature of 280 K, which is much larger than the previous works reported for hexagonal non-antiferromagnets. Our work provides a solid foundation for understanding the exchange bias of ferromagnetic/noncollinear antiferromagnetic bilayers, and we demonstrate the potential of Mn 3 Sn with unique exchange bias properties, which may contribute to the future design and construction of advanced antiferromagnetic spintronic devices. • The exchange bias effect by noncollinear antiferromagnetic materials. • Exchange bias of ferromagnetic/noncollinear antiferromagnetic bilayer samples. • Mn 3 Sn with a Kagome configuration of spin lead to novel properties in exchange bias effect. • Large exchange bias and a blocking temperature. • The potential of Mn 3 Sn with unique exchange bias properties. [ABSTRACT FROM AUTHOR]

We reported the facet controllable synthesis of BiOI nanosheets to expose {0 0 1} (BiOI-001) and {1 0 0} (BiOI-100) facets by adjusting reaction time of hydrothermal process. Photocatalytic results revealed the facet-dependent photocatalytic property for CO 2 reduction on BiOI nanosheets. Photoluminescence (PL), photocurrent, UV–vis diffuse reflectance spectra (DRS), X-ray photoelectron spectroscopy (XPS), valence-band XPS spectra and theoretical calculation results revealed that BiOI-001 have better separation efficiency of photo-induced carriers and higher CB position. These positive factors resulted in the {0 0 1}-dependent photocatalytic activity of CO 2 conversion on BiOI nanosheets. [ABSTRACT FROM AUTHOR]

Olive-green few-layered BiOI with expanded spacing of the (001) facets and oxygen vacancy is successfully synthesized and characterized. The experimental analysis and theoretical calculation demonstrate that the expanded facets spacing and oxygen vacancy of few-layered BiOI result in enhanced separation efficiency of photoinduced carriers and photon absorption efficiency. Therefore, few-layered BiOI shows much higher photocatalytic activity for CO 2 conversion than that of bulk BiOI under visible or near-infrared (NIR) light. And the apparent quantum yields (AQY) are 0.14% and 0.02% for few-layered BiOI under 420 and 700 nm monochromatic light irradiation, respectively. These findings deep our understanding of few-layered BiOX (X=Cl,Br,I) photocatalysts, and propose a new route to design high efficient photocatalysts for energy and environmental photocatalysis. [ABSTRACT FROM AUTHOR]

The thickness of 2D BiOCl nanosheets along [001] direction control the internal electric fields intensity. In order to enhance the photocatalytic properties of BiOCl, decreasing the thickness is the best choice. In this paper, black ultrathin BiOCl nanosheet (BU–BiOCl) with expanded spacing of the (001) crystal plane and oxygen vacancy was synthesized in high viscosity and alcohol group concentration glycerol system. It was characterized by X-ray diffraction patterns (XRD), X-ray photoelectron spectroscopy (XPS), X-ray photoelectron scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM), electron spin resonance (ESR), UV–vis diffuse reflectance spectra (DRS) and photoluminescence (PL) spectra. The experimental characterization and theoretical calculation results also indicated that expanded facets spacing and oxygen vacancy of as-synthesized BU-BiOCl enhanced separation efficiency of photoinduced carriers and photon absorption efficiency. Therefore, BU-BiOCl showed higher activity than bulk BiOCl for H 2 production under visible light irradiation. [ABSTRACT FROM AUTHOR]

• Crystalline orientation-related magnetic anisotropy in transition metal dichalcogenides 1T′-MoTe 2 /Co heterostructures. • Studies of magnetic anisotropy in 1T′-MoTe 2 /Co heterostructures from both experiments and first-principles calculations. • Strain effect on the induced magnetic anisotropy. • The easy axis of Co magnetic anisotropy is confirmed to be along the b -axis of MoTe 2. The semimetal transition metal dichalcogenides (TMD) MoTe 2 have attracted extensive research interests in Spintronics. The understanding of the magnetic properties of MoTe 2 /Ferromagnetic (FM) heterostructures is critical to the design of novel Spintronics-based devices. However, there is lack of research on the magnetic anisotropy of the semimetal TMD/FM. Here, we demonstrate the in-plane crystalline orientation-related magnetic properties of MoTe 2 /Co to clarify the relationship between the crystalline orientation and the magnetic anisotropy. We carried out the studies of crystalline orientation-related magnetic anisotropy in 1T′-MoTe 2 /Co heterostructures from both experiments and first-principles calculations. Our results show that for Co with different thicknesses, the easy axis of Co film is along the b -axis of MoTe 2 with uniaxial magnetic anisotropy. It is also consistent with the results of our theoretical results. When Co film thickness increases, the magnetocrystalline anisotropy (MCA) oscillates around a constant value with a lower MCA along the out-of-plane direction. Meanwhile, the demagnetization energy which increases linearly as a function of Co thickness, which would make the easy axis in-plane. Our work may give a fundamental inspiration for Spintronics based devices with semi-metallic TMDs/ferromagnetic materials. [ABSTRACT FROM AUTHOR]