Large Barocaloric Effect with High Pressure-Driving Efficiency in a Hexagonal MnNi0.77Fe0.23Ge Alloy

The hydrostatic pressure is expected to be an effective knob to tune the magnetostructural phase transitions of hexagonal MM’X alloys(M and M’denote transition metals and X represents main group elements).We perform magnetization measurements under hydrostatic pressure on an MM’X martensitic MnNi0.77Fe0.23Ge alloy.The magnetostructural transition temperature can be efficiently tuned to lower temperatures by applying moderate pressures,with a giant shift rate of-151 K/GPa.A temperature span of 30 K is obtained under the pressure,within which a large magnetic entropy change of-23 J·kg-1K-1 in a field change of 5 T is induced by the mechanical energy gain due to the large volume change.Meanwhile,a decoupling of structural and magnetic transitions is observed at low temperatures when the martensitic transition temperature is lower than the Curie temperature.These results show a multi-parameter tunable caloric effect that benefits the solid-state cooling.

Magnetic-field modulation of topological electronic state and emergent magneto-transport in a magnetic Weyl semimetal

The modulation of topological electronic state by an external magnetic field is highly desired for condensed-matter physics.Schemes to achieve this have been proposed theoretically,but few can be realized experimentally.Here,combining transverse transport,theoretical calculations,and scanning tunneling microscopy/spectroscopy(STM/S)investigations,we provide an observation that the topological electronic state,accompanied by an emergent magneto-transport phenomenon,was modulated by applying magnetic field through induced non-collinear magnetism in the magnetic Weyl semimetal EuB6.A giant unconventional anomalous Hall effect(UAHE)is found during the magnetization re-orientation from easy axes to hard ones in magnetic field,with a UAHE peak around the low field of 5 kOe.

Bimetallic nano-mushrooms with DNA-mediated interior nanogaps for high-efficiency SERS signal amplification

有为散布的提高表面的拉曼(重量的单位) 分析的 ultrasensitive 的明确的 nanogaps 抓住伟人诺言的一致包含银的金属 nanostructures。不过，有强壮、稳定的重量的单位的如此的 nanostructures 的直接合成表明极其质问的遗体。这里，我们与内部 nanogaps 为金银的 nano 蘑菇的直接合成报导一条调停 DNA 的途径。这些 nano 蘑菇的重量的单位紧张极其依赖于在金头和银帽子之间的 nanogap 的区域。我们发现 nanogaps 的形成由控制在金 nanoparticles 上标记搁浅单人赛的 DNA (ssDNA ) 的 6-carboxy-X-rhodamine (ROX ) 的表面密度是细微地悦耳的。我们与 1.0 的一个高重量的单位信号改进因素在高产量获得了 nano 蘑菇我们作为一项 retrofit 措施在 CHS 在用阶段变化材料(脉冲编码调制) 的热存储的采纳以后。结果显示那与融化 23 的温度使用脉冲编码调制 ? 訄吗？？

Phase transferring luminescent gold nanoclusters via single-stranded DNA

Atomically precise gold nanoclusters(Au NCs) are an emerging class of quantum-sized nanomaterials with discrete electronic energy levels, which has led to a range of attractive electronic and optical applications. Nevertheless, the lack of general methods to transfer Au NCs protected with hydrophobic ligands to an aqueous solution hampers their use in physiological settings. Here,we developed a single-stranded DNA-based approach that could transfer ~90% hydrophobic Au NCs into an aqueous solution.We experimentally and theoretically established that multivalent electrostatic and hydrophobic interactions between DNA strands and the hydrophobic ligand layer on Au NCs resulted in monodispersed DNA-coated Au NCs with high physical integrity in an aqueous solution. The fluorescence quantum yield of Au NCs was increased by ~13 fold, and surface-constrained DNA retained the specific recognition ability for biosensing. We further demonstrated the versatility of this phase-transfer approach, which thus holds great potential to advance biological and medical applications of Au NCs.

Aggregation-induced emission luminogen for specific identification of malignant tumour in vivo

Colorectal cancer(CRC)is still a major killer,mainly due to the lack of early detection biomarker with sensitivity/specificity.Conventional histopathology is the gold standard approach in practice,but there are still some issues(false diagnosis and long waiting period).Aggregation-induced emission(AIE)is a novel photophysical phenomenon which has been widely utilized for biological imaging in vitro,including malignant cells,showing remarkable imaging contrast and enhanced emission in high concentrated state.However,it is unclear if AIE dyes can identify malignant cells specifically in vivo.A great challenge for specific labeling of malignant cells is probably ascribed to the complex compositions in tumor tissues.Herein,an AIE dye-based mitochondria-targeted histological staining strategy was employed to localize cancer and the metastatic track in the fresh colorectal cancer.This novel approach holds great potential to revolutionize the clinical diagnosis and intervention for devastating malignancy.

Anisotropic magnetoelastic response in the magnetic Weyl semimetal Co_(3)Sn_(2)S_(2)

Co_(3)Sn_(2)S_(2) is a recently identified magnetic Weyl semimetal in Shandite compounds. Upon cooling, Co_(3)Sn_(2)S_(2) undergoes a ferromagnetic transition with c-axis polarized moments(0.3 μ_(B)/Co) around T_(C)= 175 K, followed by another magnetic anomaly around T_(A)≈ 140 K. A large intrinsic anomalous Hall effect is observed in the magnetic state below TC with a maximum of anomalous Hall angle near T_(A). Here, we report an elastic neutron scattering on the crystalline lattice of Co_(3)Sn_(2)S_(2) in a magnetic field up to 10 T. A strongly anisotropic magnetoelastic response is observed, while only a slight enhancement of the Bragg peaks is observed when B//c. The in-plane magnetic field(B//ab) dramatically suppresses the Bragg peak intensity probably by tilting the moments and lattice toward the external field direction. The in-plane magnetoelastic response commences from T_(C), and as it is further strengthened below T_(A), it becomes nonmonotonic against the field between T_(A) and T_(C) because of the competition from another in-plane magnetic order. These results suggest that a magnetic field can be employed to tune the Co_(3)Sn_(2)S_(2) lattice and its related topological states.

On the anomalous low-resistance state and exceptional Hall component in hard-magnetic Weyl nanoflakes

Magnetic topological materials, which combine magnetism and topology, are expected to host emerging topological states and exotic quantum phenomena. In this study, with the aid of greatly enhanced coercive fields in high-quality nanoflakes of the magnetic Weyl semimetal Co_(3)Sn_(2)S_(2), we investigate anomalous electronic transport properties that are difficult to reveal in bulk Co_(3)Sn_(2)S_(2) or other magnetic materials. When the magnetization is antiparallel to the applied magnetic field, the low longitudinal resistance state occurs, which is in sharp contrast to the high resistance state for the parallel case. Meanwhile, an exceptional Hall component that can be up to three times larger than conventional anomalous Hall resistivity is also observed for transverse transport. These anomalous transport behaviors can be further understood by considering nonlinear magnetic textures and the chiral magnetic field associated with Weyl fermions, extending the longitudinal and transverse transport physics and providing novel degrees of freedom in the spintronic applications of emerging topological magnets.

Spin excitations and spin wave gap in the ferromagnetic Weyl semimetal Co3Sn2S2

We report a comprehensive neutron scattering study on the spin excitations in the magnetic Weyl semimetal Co3Sn2S2 with a quasi-two-dimensional structure.Both in-plane and out-of-plane dispersions of the spin waves were revealed in the ferromagnetic state.Similarly,dispersive but damped spin excitations were found in the paramagnetic state.The effective exchange interactions were estimated using a semi-classical Heisenberg model to consistently reproduce the experimental TCand spin stiffness.However,a full spin wave gap below Eg=2.3 meV was observed at T=4 K.This value was considerably larger than the estimated magnetic anisotropy energy(~0.6 meV),and its temperature dependence indicated a significant contribution from the Weyl fermions.These results suggest that Co3Sn2S2 is a three-dimensional correlated system with a large spin stiffness,and the low-energy spin dynamics can interplay with the topological electron states.

DNA nanostructure-encoded fluorescent barcodes

Identification and differentiation of various bioanalytes with high spatial and temporal resolution have spawned fluorescent barcode-based detection and imaging.DNA nanostructures with excellent structure programmability,addressability,and nearatomic structure accuracy have emerged as a versatile platform to develop fluorescent barcodes through finely controlled dye numbers,relative distances,and compositions.A variety of DNA fluorescent barcodes with distinguishable spectral colors,geometries and digitized fluorescence intensities have been constructed and favorably implemented in the field of bioimaging,multiplex bioassay,and information security.In this review,we first summarize the state of the art of self-assembled DNA nanostructures.Next,the utilization of DNA nanostructure to develop fluorescent barcodes and the photophysical properties of DNA-templated fluorophores are reviewed.Finally,the applications of DNA fluorescent barcodes for biosensing and imaging,and the challenges and outlook of DNA nanostructure-engineered fluorescent barcodes are discussed.