Topological Magnetoresistance of Magnetic Skyrmionic Bubbles

Magnetic skyrmions offer promising prospects for constructing future energy-efficient and high-density information technology, leading to extensive explorations of new skyrmionic materials recently. The topological Hall effect has been widely adopted as a distinctive marker of skyrmion emergence. Alternately, here we propose a novel signature of skyrmion state by quantitatively investigating the magnetoresistance (MR) induced by skyrmionic bubbles in CeMn2Ge2. An intriguing finding was revealed: the anomalous MR measured at different temperatures can be normalized into a single curve, regardless of sample thickness. This behavior can be accurately reproduced by the recent chiral spin textures MR model. Further analysis of the MR anomaly allowed us to quantitatively examine the effective magnetic fields of various scattering channels. Remarkably, the analyses, combined with the Lorentz transmission electronic microscopy results, indicate that the in-plane scattering channel with triplet exchange interactions predominantly governs the magnetotransport in the Bloch-type skyrmionic bubble state. Our results not only provide insights into the quantum correction on MR induced by skyrmionic bubble phase, but also present an electrical probing method for studying chiral spin texture formation, evolution and their topological properties, which opens up exciting possibilities for identifying new skyrmionic materials and advancing the methodology for studying chiral spin textures.Comment: 17 pages,5 figures,submitte

Denary high entropy metallic glass with large magnetocaloric effect

Denary high entropy metallic glass with large magnetocaloric effec

Gasification under CO2–Steam Mixture: Kinetic Model Study Based on Shared Active Sites

In this work, char gasification of two coals (i.e., Shenfu bituminous coal and Zunyi anthracite) and a petroleum coke under a steam and CO2 mixture (steam/CO2 partial pressures, 0.025–0.075 MPa; total pressures, 0.100 MPa) and CO2/steam chemisorption of char samples were conducted in a Thermogravimetric Analyzer (TGA). Two conventional kinetic models exhibited difficulties in exactly fitting the experimental data of char–steam–CO2 gasification. Hence, a modified model based on Langmuir–Hinshelwood model and assuming that char–CO2 and char–steam reactions partially shared active sites was proposed and had indicated high accuracy for estimating the interactions in char–steam–CO2 reaction. Moreover, it was found that two new model parameters (respectively characterized as the amount ratio of shared active sites to total active sites in char–CO2 and char–steam reactions) in the modified model hardly varied with gasification conditions, and the results of chemisorption indicate that these two new model parameters mainly depended on the carbon active sites in char samples

A Salt-Assisted Combustion Method to Prepare Well-Dispersed Octahedral MnCr2O4 Spinel Nanocrystals

Well-dispersed nanocrystalline MnCr2O4 was prepared by a salt-assisted combustion process using low-toxic glycine as fuel and Mn(NO3)2 and Cr(NO3)3·9H2O as raw materials. The obtained products were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared (FT-IR) spectroscopy, Raman spectroscopy, Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM). The fabrication process was monitored by thermogravimetric and differential thermal analysis (TG-DTA). The phase formation process was detected by XRD, and MnCr2O4 single phase with high crystallinity was formed at 700°C. TEM and SEM images revealed that the products were composed of well-dispersed octahedral nanocrystals with an average size of 80 nm. Inert salt-LiCl played an important role in breaking the network structure of agglomerated nanocrystallites

Fungi residue derived carbon as highly efficient hydrogen peroxide electrocatalyst

In electrochemical devices, the reduction of dissolved oxygen in electrolyte can achieve on-site production of hydrogen peroxide. The industrial viability of the process strongly depends on cathode electrocatalyst. However, current catalysts rely on rare, noble metals and their composite. Thus, it remains a great challenge of cost-effective catalyst with both high activity and selectivity. Herein, we made use of extremely low-cost fungi residue biomass, developing a multi-non-precious metal doped carbon catalyst (named as FRC) for H2O2 electrogeneration by facile in-situ synthesis. The one-step prepared FRC balances the performance of different metal oxides and exhibits not only high activity but also high selectivity at a spacious potential range. Specifically, the current density for ring reaches 0.45 mA cm(-2) at -0.5 V (vs SCE). Besides, the selectivity achieves 98% and remain above 91% in wide potential range (-0.7 similar to -0.3 V), which exceeds almost all metal contained carbon materials to our knowledge. As the first study of fungi residue towards H2O2 electrogeneration, this novel approach provides a highly promising and low cost electrocatalyst for real production, moreover, exploring a new direction for H2O2 electrocatalyst development. (C) 2017 Elsevier Ltd. All rights reserved.</p

Study of the effect of weak magnetic field on the decolorization of azo dye by Fe-based amorphous alloy powders

Fe-Si-B amorphous alloy ribbons were melt-spun, and the amorphous powders were made by ball-milling the ribbons. The azo dye direct blue 2B was decolorized by the amorphous alloy powders. We made apreliminary study towards the weak magnetic field's effect on the decolorization of azo dye by Fe-based amorphous alloy powders via manipulating the magnetic field intensity generated by the Helmholtz coils, the dosage of the amorphous alloy powders. It was found that within certain magnetic field intensity range, increasing the intensity will result in the increase of decolorization rate. With H=3 980 A/m, the t_(1/2) was 5.0 min, and the decolorization rate was increased by 40% compared to that of H=0 A/m. With the increase of the Fe-based amorphous alloy powder dosage, the positive impact of the magnetic field on the decolorization rate was improved at firstand then stabilized

Influence of Meteorological Factors and Chemical Processes on the Explosive Growth of PM2.5 in Shanghai, China

In order to explore the mechanism of haze formation, the meteorological effect and chemical reaction process of the explosive growth (EG) of PM2.5 were studied. In this study, the level of PM2.5, water-soluble inorganic ions, carbonaceous aerosols, gaseous precursors, and meteorological factors were analyzed in Shanghai in 2018. The EG event is defined by a net increase of PM2.5 mass concentration greater than or equal to 100 &mu;g m&minus;3 within 3, 6, or 9 h. The results showed that the annual average PM2.5 concentration in Shanghai in 2018 was 43.2 &mu;g m&minus;3, and secondary inorganic aerosols and organic matter (OM) accounted for 55.8% and 20.1% of PM2.5, respectively. The increase and decrease in the contributions of sulfate, nitrate, ammonium (SNA), and elemental carbon (EC) to PM2.5 from clean days to EG, respectively, indicated a strong, secondary transformation during EG. Three EG episodes (Ep) were studied in detail, and the PM2.5 concentration in Ep3 was highest (135.7 &mu;g m&minus;3), followed by Ep2 (129.6 &mu;g m&minus;3), and Ep1 (82.3 &mu;g m&minus;3). The EG was driven by stagnant conditions and chemical reactions (heterogeneous and gas-phase oxidation reactions). This study improves our understanding of the mechanism of haze pollution and provides a scientific basis for air pollution control in Shanghai