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Novel Luminescent Multilayer Films with Magnetic and Electronic Microenvironment
摘要： Luminescent multilayer thin films (MTFs) based on exfoliated magnetic layered double hydroxides (LDHs) with/without oppositely-charged montmorillonite (MMT) nanosheets were fabricated via layer-by-layer self-assembly method. In this work, we chose transition metal-bearing LDHs nanosheets to offer magnetic field for the chromophores. At the same time, the oppositely-charged nanosheets can provide additional electronic microenvironment (EME). As a result, both EME and magnetic field have remarkable influences on enhancing the luminescent lifetimes of chromophores, which suggests a new pathway to develop the novel light-emitting materials and optical devices.
关键词： Montmorillonite,Electronic Microenvironment,Magnetic Field,Layered Double Hydroxides,Luminescence
更新于2025-09-23 15:22:29
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The rotationally modulated polarization of ξ Boo A
摘要： We have observed the active star ξ Boo A (HD 131156A) with high precision broadband linear polarimetry contemporaneously with circular spectropolarimetry. We find both signals are modulated by the 6.43 d rotation period of ξ Boo A. The signals from the two techniques are 0.25 out of phase, consistent with the broadband linear polarization resulting from differential saturation of spectral lines in the global transverse magnetic field. The mean magnitude of the linear polarization signal is ～4 ppm G–1 but its structure is complex and the amplitude of the variations suppressed relative to the longitudinal magnetic field. The result has important implications for current attempts to detect polarized light from hot Jupiters orbiting active stars in the combined light of the star and planet. In such work stellar activity will manifest as noise, both on the time-scale of stellar rotation, and on longer time-scales – where changes in activity level will manifest as a baseline shift between observing runs.
关键词： stars: individual HD 131156A,stars: magnetic field,polarization,stars: activity
更新于2025-09-23 15:22:29
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Magnetic-field-dependent quantum emission in hexagonal boron nitride at room temperature
摘要： Optically addressable spins associated with defects in wide-bandgap semiconductors are versatile platforms for quantum information processing and nanoscale sensing, where spin-dependent inter-system crossing transitions facilitate optical spin initialization and readout. Recently, the van der Waals material hexagonal boron nitride (h-BN) has emerged as a robust host for quantum emitters, promising efficient photon extraction and atom-scale engineering, but observations of spin-related effects have remained thus far elusive. Here, we report room-temperature observations of strongly anisotropic photoluminescence patterns as a function of applied magnetic field for select quantum emitters in h-BN. Field-dependent variations in the steady-state photoluminescence and photon emission statistics are consistent with a spin-dependent inter-system crossing between triplet and singlet manifolds, indicating that optically-addressable spin defects are present in h-BN.
关键词： photoluminescence,room temperature,quantum emitters,magnetic field,hexagonal boron nitride,spin defects
更新于2025-09-23 15:22:29
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Sources of heading errors in optically pumped magnetometers operated in the Earth's magnetic field
摘要： When optically pumped magnetometers are aimed for use in the Earth’s magnetic field, the orientation of the sensor to the field direction is of special importance to achieve accurate measurement results. Measurement errors and inaccuracies related to the heading of the sensor can be an even more severe problem in the case of special operational configurations, such as the use of strong off-resonant pumping. We systematically study the main contributions to the heading error in systems that promise high magnetic field resolutions at the Earth’s magnetic field strengths, namely the nonlinear Zeeman splitting and the orientation-dependent light shift. The good correspondence of our theoretical analysis to experimental data demonstrates that both of these effects are related to a heading-dependent modification of the interaction between the laser light and the dipole moment of the atoms. Also, our results promise a compensation of both effects using a combination of clockwise and counterclockwise circular polarization.
关键词： optically pumped magnetometers,circular polarization,Earth's magnetic field,light shift,nonlinear Zeeman splitting,heading error
更新于2025-09-23 15:22:29
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Synthesis and Properties of Novel Thiophene-Based Liquid Crystalline Conducting Polymers
摘要： Side-chain liquid crystalline polythiophenes were synthesised and the effects of the mesogenic units on the structure and electronic properties of the polymers were studied. The liquid crystal properties of the polymer films were studied using polarised hot-stage optical microscopy and differential scanning calorimetry, and X-ray diffractometry was used to investigate the effect of a magnetic field on the monomers and polymers.
关键词： Polythiophene,Conducting polymers,Liquid crystals,X-ray diffraction,Magnetic field
更新于2025-09-23 15:22:29
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Distortion of Magnetic Fields in a Starless Core. V. Near-infrared and Submillimeter Polarization in FeSt 1-457
摘要： The relationship between submillimeter dust emission polarization and near-infrared (NIR) H-band polarization produced by dust dichroic extinction was studied for the cold starless dense core FeSt 1–457. The distributions of polarization angles (90°-rotated for the submillimeter) and degrees were found to be very different between submillimeter and NIR wavelengths. The mean polarization angles for FeSt 1-457 at submillimeter and NIR wavelengths are 132°. 1 ± 22°. 0 and 2°. 7 ± 16°. 2, respectively. The correlation between PH and AV was found to be linear from the outermost regions to the relatively dense lines of sight of AV ≈ 25 mag, indicating that NIR polarization reflects the overall polarization (magnetic field) structure of the core, at least in this density range. The flat PH/AV versus AV correlations were confirmed, and the polarization efficiency was found to be comparable to the observational upper limit. On the other hand, as reported by Alves et al. submillimeter polarization degrees show a clear linearly decreasing trend against AV from AV ≈ 20 mag to the densest center (AV ≈ 41 mag), appearing as a 'polarization hole' structure. The power-law index for the Psubmm versus AV relationship was obtained to be ≈?1, indicating that the alignment for the submillimeter-sensitive dust is lost. These very different polarization distributions at submillimeter and NIR wavelengths suggest either that (1) there are different radiation environments at these wavelengths or (2) submillimeter-sensitive dust is localized or (3) a combination of both.
关键词： polarization,dust, extinction,stars: magnetic field,ISM: clouds,stars: formation
更新于2025-09-23 15:22:29
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Coupling Effect of Magnetic Fields on Piezotronic and Piezo-Phototronic Properties of ZnO and ZnO/Co <sub/>3</sub> O <sub/>4</sub> Core/Shell Nanowire Arrays
摘要： Piezoelectric-related multi-property coupling effects have recently attracted much attention for developing next generation multi-functional devices. In this paper, the multi-property coupling effects among magnetic field, piezoelectricity and photoexcitation were investigated in ZnO nanowire arrays. The response of the current flowing through the array to the applied magnetic field was decreasing with increasing magnetic field strength. However, due to piezo-magnetotronic effect, the magnetically induced current was magnified by one order of magnitude by applying an external stress. In contrast, under UV light illumination, the magnetically induced current response increased with an increment of magnetic field strength, as the magnetic field is favorable to the separation of photo-induced electron-hole pairs. The magnetically-induced current response was enhanced by at least two orders of magnitude due to the piezo-photo-magnetotronic effect. Furthermore, ZnO/Co3O4 core/shell heterojunction nanowire arrays was employed to improve the current responses up to 9 times and 3 times, under piezo-magnetotronic and piezo-photo-magnetotronic engagements, respectively, attributed to the improved charge carrier separation and transportation at the core/shell interface. This phenomenon projects a potential for multi-functional piezo-magnetotronic and piezo-photo-magnetotronic device development.
关键词： Piezotronic effect,Magnetic Field,Piezo-Photo-Magnetotronic effect,Piezo-Magnetotronic effect
更新于2025-09-23 15:21:21
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Binding energy and optical absorption of donor impurity states in “12-6” tuned GaAs/GaAlAs double quantum well under the external fields
摘要： We have investigated the binding energies of the s-symmetric ground and first excited shallow donor impurity states and the total 1s → 2s absorption coefficient, including the first and third order corrections, in "12-6" tuned GaAs/GaAlAs double quantum well as a function of the impurity position, size of the structure, and the electric and magnetic field intensities. The obtained results show that the electronic and optical properties of tuned GaAs/GaAlAs double quantum well can be adjustable by an appropriate choice of the sample geometry, material parameters and applied external fields which will lead to new potential applications in optoelectronics.
关键词： Double quantum well,Absorption coefficient,Electric and magnetic field,Donor impurity
更新于2025-09-23 15:21:21
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Effect of Static Magnetic Field on the Evolution of Residual Stress and Microstructure of Laser Remelted Inconel 718 Superalloy
摘要： As a typical additive manufacturing technique, direct energy deposition is restricted from further application due to the presence of residual stress and the structural deformation. Thus, minimizing the residual stress plays a crucial role in additive manufacturing. In this work, a transverse static magnetic field is introduced in the laser remelting of Inconel 718 superalloy to investigate the effects on residual stress and microstructural change. The x-ray diffraction technique was used to examine the residual stress variation. Optical microscope and scanning electron microscope were applied to observe the microstructure evolution. It was found that the compressive residual stress of the remelted region was notably reduced from 392.50 to 315.45 MPa under the effect of the magnetic field of 0.55 T. Furthermore, it was observed that the average dendrite spacing was reduced by about 32% under the magnetic field. During the laser remelting process, the imposed electromagnetic force minimized the flow field within the molten pool, inhibiting the heat transfer and minimizing the cooling rate. These directly reduced the residual stresses. Based on research findings, the magnetic field can be a potential method to eliminate the residual stress in laser additive manufacturing components.
关键词： laser direct deposition,static magnetic field,Inconel 718 superalloy,laser remelting,residual stress,thermoelectric magnetic force
更新于2025-09-23 15:21:01
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Influence of DC electric and magnetic fields on silicon solar cells/modules
摘要： In this study, the impact of DC electric and magnetic fields on the output power, open-circuit voltage, and photocurrent density of a silicon photovoltaic (PV) cell/module is assessed. In this regard, the influence of DC electric and magnetic fields is first evaluated in theory by formulating and discussing related basis and concepts. Then, experimental measurements and data obtained from two different sets of experiments are given that verify theoretical results. In theory and practice, it is shown that depending on the direction of a DC electric field applied to a silicon PV cell/module, it causes an increase or reduction in the output power and open-circuit voltage of the PV cell/module. In detail, when the DC electric field points in the direction of the junction electric field of the PV cell(s), the output power and open-circuit voltage of the silicon PV cell/module increase, otherwise the output power and open-circuit voltage decrease. Regarding the magnetic field, it is proved that depending on the direction of a DC magnetic field applied to a silicon PV cell/module, different effects are observed. In detail, when the DC magnetic field points along the junction electric field of the PV cell(s), it has no effect on the output power and open-circuit voltage of the silicon PV cell/module. But, the output power and open-circuit voltage of the silicon PV cell/module decrease when the DC magnetic field points in the other directions. Moreover, the reduction in the output power and open-circuit voltage reaches its peak when the DC magnetic field is applied in the direction perpendicular to the junction electric field.
关键词： DC electric field,solar energy,silicon PV cell,silicon PV module,DC magnetic field
更新于2025-09-23 15:21:01