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167 results on '"Shen, Hongxian"'

19. Topological magnetoresistance of magnetic skyrmionic bubbles.

Author

Li, Fei, Nie, Hao, Zhao, Yu, Zhao, Zhihe, Huo, Juntao, Wang, Tianyang, Liao, Zhaoliang, Liu, Andi, Guo, Hanjie, Shen, Hongxian, Jiang, Sida, Chen, Renjie, Yan, Aru, Cheong, S.-W., Xia, Weixing, Sun, Jianfei, and Zhang, Lunyong

Subjects
MAGNETORESISTANCE, HALL effect, INFORMATION technology, TRANSMISSION electron microscopy, MAGNETIC fields, CHIRALITY of nuclear particles, ELECTRICAL steel
Abstract

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 electron 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. [ABSTRACT FROM AUTHOR]

Published
2024
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46. Significant Structure Modulation in Polar Antiferromagnet FeCoMo3O8.

Author

Zhang, Chenjia, Zhao, Yu, Nie, Hao, Zheng, Can, Li, Fei, Zhou, Dingran, Gao, Ruishuai, Shen, Hongxian, Jiang, Sida, Zhang, Lunyong, and Sun, Jianfei

Subjects
MAGNETOELECTRIC effect, LATTICE constants, UNIT cell, CELL size, ELECTRONIC structure
Abstract

The discovery of giant magnetoelectric effect in Fe2Mo3O8 has sparked considerable interest in investigating the novel effects of M2Mo3O8 (M = Zn, Mn, Fe, Co, Ni) family, in particular the emergent physics driven by the M‐site ions. Herein, the structural evolution due to M‐site mixing is studied in the compound FeCoMo3O8 whose unit cell volume and lattice constant are slightly tuned compared with those of Fe2Mo3O8 and Co2Mo3O8. However, significant structure distortion occurs on the octahedron and tetrahedron as a result of the relaxation of the unbalanced force, caused by the distinction of the M ion radius in the mixing case. The octahedron and tetrahedron are shifted toward each other along the c‐axis which increases the coplanarity of the Fe and Co ions. The octahedron is compressed along the D3d‐symmetry axis and its bonds are elongated significantly. A complex tension‐like distortion is induced for the tetrahedron. Its bond along the C3v‐symmetry axis is elongated and other three bonds are shortened. The study demonstrates that ions mixing at the M sites would introduce intrigue structure modulation in the M2Mo3O8 family, which would tune the electronic orbit structure. This may shed new light on understanding the emergent behaviors of the material family. [ABSTRACT FROM AUTHOR]

Published
2023
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47. Enhanced magnetocaloric properties of annealed melt-extracted Mn1.3Fe0.6P0.5Si0.5 microwires

Author

Luo, Lin, Law, Jia Yan, Shen, Hongxian, Moreno Ramírez, Luis Miguel, Franco García, Victorino, Guo, Shu, Phan, Manh-Huong, Universidad de Sevilla. Departamento de Física de la Materia Condensada, National Natural Science Foundation of China (NSFC), Ministerio de Ciencia e Innovación (MICIN). España, Agencia Estatal de Investigación. España, Junta de Andalucía, and China Scholarship Council (CSC)

Subjects
magnetocaloric effect, melt-extraction technique, (Mn,Fe)2 (P,Si) microwires, microstructure
Abstract

The highly regarded Fe2P-based magnetocaloric materials are usually fabricated by ball milling, and require an additional extended annealing treatment at high temperatures (at temperatures up to 1423 K for several hours to days). In this work, we show that fabricating Mn1.3Fe0.6P0.5Si0.5 into the form of microwires attained 82.1 wt.% of the desired Fe2P phase in the as-cast state. The microwires show a variable solidification structure along the radial direction; close to the copper wheel contact, Fe2P phase is in fine grains, followed by dendritic Fe2P grains and finally secondary (Mn,Fe)5Si3 phase in addition to the dendritic Fe2P grains. The as-cast microwires undergo a ferroto para-magnetic transition with a Curie temperature of 138 K, showing a maximum isothermal magnetic entropy change of 4.6 J kg−1 K −1 for a magnetic field change of 5 T. With further annealing, a two-fold increase in the maximum isothermal magnetic entropy change is found in the annealed microwires, which reveal 88.1 wt.% of Fe2P phase. National Natural Science Foundation de China - NSFC 51871124 Ministerio de Ciencia e Innovación y Agencia Estatal de Investigación, de España MCIN/AEI - PID2019-105720RB-I00 Consejería de Economía, Conocimiento, Empresas y Universidad de la Junta de Andalucía - P18-RT-746 China Scholarship Council - CSC 202006120203

Published
2022

48. A perspective magnetic bed comprising Gd alloy multi-microwires for energy-efficient magnetic refrigeration

Author

Shen, Hongxian, Luo, Lin, Jiang, Sida, Liu, Jingshun, Liu, Yanfen, Huang, Yongjiang, Zhang, Lunyong, Sun, Jianfei, Belliveau, Hillary, and Phan, Manh-Huong

Subjects
FOS: Physical sciences, Applied Physics (physics.app-ph), Physics - Applied Physics
Abstract

We have designed a new magnetic bed structure with desirable table-like magnetocaloric effect (MCE) by using three kinds of soft ferromagnetic Gd-Al-Co microwire arrays with different Curie temperatures ($T_C$). The $T_C$ interval of these three wires is ~10 K and the designed new structure named Sample A. This sample shows a smooth table-like magnetic entropy change ($\Delta S_M$) at high applied field change ($\mu_0 \Delta H=5 T$) ranging from ~92 K to ~107 K. The maximum entropy change ($-\Delta S_M^{\rm max}$) and refrigerant capacity (RC) for Sample A at $\mu_0 \Delta H=5 T$ are calculated to be ~9.42 Jkg$^{-1}$K$^{-1}$ and ~676 Jkg$^{-1}$. The calculated curves of $-\Delta S_M(T)$ and the corresponding experimental data match well with each other, suggesting that the desirable magnetocaloric properties of the microwire arrays can be designed. Simulation shows that the RC values of the designed systems increase when increasing the interval of $T_C$. The table-like MCE and the enhanced heat-transfer efficiency due to the enhanced surface areas of the microwires make this newly designed magnetic bed very promising for use in energy-efficient magnetic refrigerators.

Published
2021

49. Hot Deformation Behavior of a Co-Spray-Formed Al-Si/7075 Bimetallic Gradient Alloy

Author

Xu Gu, Song Heqian, Lei Yu, Fuyang Cao, Jianfei Sun, Sida Jiang, Shen Hongxian, and Lunyong Zhang

Subjects
Materials science, Mining engineering. Metallurgy, Silicon, Alloy, Metals and Alloys, TN1-997, chemistry.chemical_element, Activation energy, Strain rate, engineering.material, Flow stress, Arrhenius plot, hot deformation behavior, chemistry, engineering, General Materials Science, Compression (geology), Deformation (engineering), Composite material, spray-deposited, functionally graded materials, constitutive equation
Abstract

In this paper, we report the results obtained from the hot compression behaviour of co-spray-formed Al-Si/7075 bimetallic gradient alloys by investigating the five selected layers divided evenly from top to bottom. It was found that with a decrease in the strain rate and an increase in temperature, the hot compression flow stress of deposited alloys decreases gradually, as expected. The relationship between flow stress, temperature and strain rate follows the Arrhenius relationship. The deformation activation energy of the co-spray formed gradient alloy gradually increases from bottom to top in the height direction, which are 100.15, 167.35, 185.54, 208.78 and 220.83 KJ/mol, indicating that the degree of difficulty in the deformation of the alloy is affected by changes in the silicon content of the alloy. Finally, the flow stress constitutive equation is calculated for each layer of alloy material, which is instructive for the subsequent study of the densification process of co-spray-formed gradient alloys.

Published
2021

50. Martensitic Transition and Superelasticity of Ordered Heat Treatment Ni-Mn-Ga-Fe Microwires.

Author

Liu, Yanfen, Lang, Zirui, Shen, Hongxian, Liu, Jingshun, and Sun, Jianfei

Subjects
HEAT treatment, PHASE transitions, FIELD emission electron microscopy, MARTENSITIC transformations, CLAUSIUS-Clapeyron relation, STRESS-strain curves, FLAMMABILITY
Abstract

The preparation of Ni-Mn-Ga and Ni-Mn-Ga-Fe master alloy ingots and microwires was completed by high vacuum electric furnace melt melting furnace and melt drawing liquid forming equipment, and the lattice dislocations and defects formed inside the microwires during the preparation process were corrected by stepwise ordered heat treatment. The micro-structure and phase structure were characterized using a SEM field emission scanning electron microscopy and an XRD diffractometer combined with an EDS energy spectrum analyzer; the martensitic phase transformation process of the microwires was analyzed using a DSC differential scanning calorimeter; and the superelasticity of the microwires was tested by a Q800 dynamic mechanical analyzer. The results indicate that Fe doping can refine the grain, transform the phase structure from parent phase to single 7M martensite, reduce the number of martensitic variants, and increase the mobility of the twin grain boundary interface. The MT phase transition temperature (MS) is substantially increased in the martensite transition (MT) process by the increase of the number of free electrons in its lattice. During the superelasticity (SE) test, both microwires displayed superior recover-ability of SE curves, and the Fe doping curves showed similar characteristics of "linear superelasticity", showing higher critical stress values and complete SE in the experiment. The critical stress satisfies the Clausius-Clapeyron equation and exhibits higher temperature sensitivity than Ni-Mn-Ga microwires. [ABSTRACT FROM AUTHOR]

Published
2022
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