Anisotropic superconducting properties including the upper critical field Hc2, thermal activation energy U0, and critical current density Jc are systematically studied in a large Ca1−xLaxFeAs2 single crystal (x ∼ 0.18). The obtained Hc2 bears a moderate anisotropy γ of approximately 2–4.2, located between those of “122” Ba1−xKxFe2As2 (1 < γ < 2) and “1111” NdFeAsO1−xFx (5 < γ < 9.2). Both the magnitude of U0 and its field dependence are very similar to those of NdFeAsO1−xFx, also indicating anisotropic superconductivity. Moreover, high and anisotropic Jc’s exceeding 105 A/cm2 have been calculated from the magnetization hysteresis loops, indicating the existence of strong bulk-dominated pinning in the present superconducting material.
The rapid advancements of wearable electronics require continued innovation in sustainable power sources and human interactive sensors. An abundance of energy in various forms, such as mechanical, thermal, optical, and sound are ubiquitous in the environment and human activities. Currently, hybrid generators using piezoelectric polymers with relatively low piezoelectric and pyroelectric constants have been fabricated to simultaneously scavenge mechanical and thermal energies. In this work, micro-patterned single-crystal PMN-PT Received: ((will be filled in by the editorial staff)) Revised: ((will be filled in by the editorial staff)) Published online: ((will be filled in by the editorial staff))
Two-dimensional (2D)
Co-based MOF-on-MOF heterojunction nanostructures
with improved electrocatalytic activity were successfully constructed
via a mild two-step solution route, employing Co2+ ions
as the center atoms, and 1,4-benzenedicarboxylate (BDC) and 4,4′-biphenyldicarboxylate
(BPDC) as ligands. The as-obtained heterojunction nanostructures were
characterized by field-emission scanning electron microscopy (FESEM),
X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy,
Brunauer-Emmett-Teller (BET) surface area analysis, thermogravimetric
analysis (TGA), and X-ray photoelectron spectroscopy (XPS) technologies.
Electrochemical measurements showed that as-prepared Co-BPDC/Co-BDC
heterojunction nanostructures presented markedly enhanced OER electrocatalytic
activity, compared with single Co-BPDC, Co-BDC, and/or their physical
mixture. Also, the Co-BPDC/Co-BDC-3 heterojunction prepared after
treatment for 3 h exhibited the strongest catalytic activity. To reach
the current density j
geo = 10 mA cm–2, the Co-BPDC/Co-BDC-3 heterojunction-modified glassy
carbon electrode required an overpotential of 335 mV in 1 M KOH, which
was reduced by 57 and 93 mV, compared to the electrodes modified by
Co-BDC and Co-BPDC, respectively. Simultaneously, the heterojunction
catalyst also displayed better long-term stability. The improvement
of the above performances should be attributed to the increased structure
stability, BET surface area, ECSA, and electron transfer ability of
the heterojunction.
Vertical gold-nanogaps are created on microtubular cavities to explore the coupling between resonant light supported by the microcavities and surface plasmons localized at the nanogaps. Selective coupling of optical axial modes and localized surface plasmons critically depends on the exact location of the gold-nanogap on the microcavities which is conveniently achieved by rolling-up specially designed thin dielectric films into three dimensional microtube ring resonators. The coupling phenomenon is explained by a modified quasi-potential model based on perturbation theory. Our work reveals the coupling of surface plasmon resonances localized at the nanoscale to optical resonances confined in microtubular cavities at the microscale, implying a promising strategy for the investigation of light-matter interactions.
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