arXiv: Materials Science最新文献_第4页

Measurement of Volume Changes and Associated Stresses in Ge Electrodes Due to Na/Na+ Redox Reactions Na/Na+氧化还原反应引起的Ge电极体积变化和相关应力的测量

arXiv: Materials Science Pub Date : 2020-11-25 DOI: 10.1149/1945-7111/abd5fc

S. Rakshit, A. Pakhare, Olivia Ruiz, M. Khoshi, E. Detsi, Huixin He, V. Sethuraman, S. Nadimpalli

{"title":"Measurement of Volume Changes and Associated Stresses in Ge Electrodes Due to Na/Na+ Redox Reactions","authors":"S. Rakshit, A. Pakhare, Olivia Ruiz, M. Khoshi, E. Detsi, Huixin He, V. Sethuraman, S. Nadimpalli","doi":"10.1149/1945-7111/abd5fc","DOIUrl":"https://doi.org/10.1149/1945-7111/abd5fc","url":null,"abstract":"In situ electrochemical cells were assembled with an amorphous germanium (a-Ge) film as working electrode and sodium foil as reference and counter electrode. The stresses generated in a-Ge electrodes due to electrochemical reaction with sodium were measured in real-time during the galvanostatic cycling. A specially designed patterned a-Ge electrode was cycled against sodium and the corresponding volume changes were measured using an AFM; it was observed that sodiation/desodiation of a-Ge results in more than 300% volume change, consistent with literature. The potential and stress response showed that the a-Ge film undergoes irreversible changes during the first sodiation process, but the subsequent desodiation/sodiation cycles are reversible. The stress response of the film reached steady-state after the initial sodiation and is qualitatively similar to the response of Ge during lithiation, i.e., initial linear elastic response followed by extensive plastic deformation of the film to accommodate large volume changes. However, despite being bigger ion, sodiation of Ge generated lower stress levels compared to lithiation. Consequently, the mechanical dissipation losses associated with plastic deformation are lower during sodiation process than it is for lithiation.","PeriodicalId":8467,"journal":{"name":"arXiv: Materials Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86230816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Tuning the spontaneous exchange bias effect with Ba to Sr partial substitution in La1.5(Sr0.5−xBax)CoMnO6 La1.5(Sr0.5−xBax)CoMnO6中Ba - Sr部分取代调节自发交换偏置效应

arXiv: Materials Science Pub Date : 2020-11-24 DOI: 10.1063/5.0028663

M. Boldrin, A. G. Silva, L. T. Coutrim, J. Jesus, C. Macchiutti, E. M. Bittar, L. Bufaiçal

引用次数: 11

Uniaxial Néel vector control in perovskite oxide thin films by anisotropic strain engineering 各向异性应变工程控制钙钛矿氧化物薄膜中的单轴nsamel矢量

arXiv: Materials Science Pub Date : 2020-11-24 DOI: 10.1103/PhysRevB.103.224435

K. Kjærnes, I. Hallsteinsen, R. Chopdekar, M. Moreau, T. Bolstad, Ingeborg-Helene Svenum, S. Selbach, T. Tybell

引用次数: 1

Neutron study of magnetic correlations in rare-earth-free Mn-Bi magnets 无稀土Mn-Bi磁体中磁相关性的中子研究

arXiv: Materials Science Pub Date : 2020-11-23 DOI: 10.1103/PHYSREVMATERIALS.5.034407

A. Malyeyev, Ivan Titov, P. Bender, M. Bersweiler, V. Pipich, S. Muhlbauer, S. Ener, O. Gutfleisch, A. Michels

引用次数: 3

Crystal structure prediction by combining graph network and Bayesian optimization 结合图网络和贝叶斯优化的晶体结构预测

arXiv: Materials Science Pub Date : 2020-11-22 DOI: 10.21203/rs.3.rs-814684/v1

Guanjian Cheng, X. Gong, W. Yin

引用次数: 1

Built-in electric field control of magnetic coupling in van der Waals semiconductors 范德华半导体中磁耦合的内置电场控制

arXiv: Materials Science Pub Date : 2020-11-22 DOI: 10.1103/PhysRevB.103.L140410

Chengxi Huang, Jing-Han Guan, Qiongyu Li, Fang Wu, P. Jena, E. Kan

引用次数: 3

Tetragonality mapping of martensite in a high‑carbon steel by EBSD 用EBSD对高碳钢中马氏体的四方映射

arXiv: Materials Science Pub Date : 2020-11-20 DOI: 10.1016/J.MATCHAR.2021.111040

G. Nolze, A. Winkelmann, G. Cios, T. Tokarski

引用次数: 10

Pressure controlled trimerization for switching of anomalous Hall effect in triangular antiferromagnet Mn3Sn 三角形反铁磁体Mn3Sn中异常霍尔效应开关的压力控制三聚化

arXiv: Materials Science Pub Date : 2020-11-20 DOI: 10.1103/PhysRevResearch.2.043366

C. Singh, Vikram Singh, Gyandeep Pradhan, V. Srihari, H. Poswal, R. Nath, A. Nandy, A. Nayak

{"title":"Pressure controlled trimerization for switching of anomalous Hall effect in triangular antiferromagnet \u0000Mn3Sn","authors":"C. Singh, Vikram Singh, Gyandeep Pradhan, V. Srihari, H. Poswal, R. Nath, A. Nandy, A. Nayak","doi":"10.1103/PhysRevResearch.2.043366","DOIUrl":"https://doi.org/10.1103/PhysRevResearch.2.043366","url":null,"abstract":"Here, we present a detailed theoretical and experimental study on the pressure induced switching of anomalous Hall effect (AHE) in the triangular antiferromagnetic (AFM) compound Mn$_3$Sn. Our theoretical model suggests pressure driven significant splitting of the in-plane Mn bond lengths $i.e.$ an effective trimerization, which in turn stabilizes a helical AFM ground state by modifying the inter-plane exchange parameters in the system. We experimentally demonstrate that the AHE in Mn$_3$Sn reduces from 5$muOmega$ cm at ambient pressure to zero at an applied pressure of about 1.5 GPa. Furthermore, our pressure dependent magnetization study reveals that the conventional triangular AFM ground state of Mn$_3$Sn systematically transforms into the helical AFM phase where the symmetry does not support a non-vanishing Berry curvature required for the realization of a finite AHE. The pressure dependent x-ray diffraction (XRD) study rules out any role of structural phase transition in the observed phenomenon. In addition, the temperature dependent in-plane lattice parameter at ambient pressure is found to deviate from the monotonic behavior when the system enters into the helical AFM phase, thereby, supporting the proposed impact of trimerization in controlling the AHE. We believe that the present study makes an important contribution towards understanding the stabilization mechanism of different magnetic ground states in Mn$_3$Sn and related materials for their potential applications pertaining to AHE switching.","PeriodicalId":8467,"journal":{"name":"arXiv: Materials Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89517573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Exchange interactions and magnetic force theorem 交换相互作用和磁力定理

arXiv: Materials Science Pub Date : 2020-11-20 DOI: 10.1103/PHYSREVB.103.104428

I. Solovyev

{"title":"Exchange interactions and magnetic force theorem","authors":"I. Solovyev","doi":"10.1103/PHYSREVB.103.104428","DOIUrl":"https://doi.org/10.1103/PHYSREVB.103.104428","url":null,"abstract":"We critically reexamine the problem of interatomic exchange interactions, which describe the total energy change caused by infinitesimal rotations of spins near some equilibrium state. For the small variations, such interactions can be always related to the response function. However, the form of this relation can depend on additional approximations. Particularly, the commonly used magnetic force theorem (MFT) prescribes the linear relation between the exchange interactions and the response function, while the exact theory requires this dependence to be inverse. We explore the origin and consequences of these differences in the definition for the wide class of materials: ferromagnetic Ni, antiferromagnetic NiO, half-metallic CrO2, multiferroic HoMnO3, and layered magnets CrCl3 and CrI3. While in most of these cases, MFT produces quite reasonable results and can be rigorously justifies in the long wavelength and strong-coupling limits, the exact formulation appears to be more consistent, especially in dealing with two important issues, which typically arise in the theory of exchange interactions: (i) the treatment of the ligand states, and (ii) the choice of the suitable variable for the description of infinitesimal rotations of spins. Both issues can be efficiently resolved by employing the ideas of adiabatic spin dynamics supplemented with the exact expression for the exchange interactions. Particularly, we propose a simple \"downfolding\" procedure for the elimination of the ligand spins by transferring their effect to the interaction parameters between the localized spins. Furthermore, we argue that the rotations of spin moments are more suitable for the description of low-energy excitations, while the rotations of the whole magnetization matrix cause much stronger perturbation in the system of spins.","PeriodicalId":8467,"journal":{"name":"arXiv: Materials Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88241945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 11

Predicting anomalous quantum confinement effect in van der Waals materials 预测范德华材料中的反常量子约束效应

arXiv: Materials Science Pub Date : 2020-11-19 DOI: 10.1103/PhysRevMaterials.5.054602

Kamal Choudhary, F. Tavazza

{"title":"Predicting anomalous quantum confinement effect in van der Waals materials","authors":"Kamal Choudhary, F. Tavazza","doi":"10.1103/PhysRevMaterials.5.054602","DOIUrl":"https://doi.org/10.1103/PhysRevMaterials.5.054602","url":null,"abstract":"Materials with van der Waals-bonding are known to exhibit quantum confinement effect, in which the electronic bandgap of the three-dimensional (3D) realization of a material is lower than that of its two-dimensional (2D) counterpart. However, the possibility of an anomalous quantum confinement effect (AQCE) exists, where the bandgap trend is reversed. In this work, we computationally identify materials for which such AQCE occurs. Using density functional theory (DFT), we compute ~1000 OptB88vdW (semi-local functional), ~50 HSE06 and ~50 PBE0 (hybrid functional) bandgaps for bulk and their corresponding monolayers in the JARVIS-DFT database. OptB88vdW identifies 65 AQCE materials, but the hybrid functionals only confirm such finding in 14 cases. Some of the AQCE systems identified through HSE06 and PBE0 are: hydroxides or oxide hydroxide compounds (AlOH2, Mg(OH)2, Mg2H2O3, Ni(OH)2, SrH2O3) as well as Sb-halogen-chalcogenide compounds (SbSBr, SbSeI) and alkali-chalcogenides (RbLiS and RbLiSe). A detailed electronic structure analysis, based on band-structure and projected density of states, shows AQCE is often characterized by lowering of the conduction band in the monolayer and corresponding changes in the pz electronic orbital contribution, with z being the non-periodic direction in the 2D case. We believe our computational results would spur the effort to validate the results experimentally and will have impact on bandgap engineering applications based on low-dimensional materials.","PeriodicalId":8467,"journal":{"name":"arXiv: Materials Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88342292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7