检索结果-南通市图书馆

In-Situ Atomic-Scale Observation of Brownmillerite to Ruddlesden-Popper Phase Transition Tuned by Epitaxial Strain in Cobaltites

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2024年第4期41卷 152-158页

作者：林挺高昂汤哲歆林炜光孙慕华张庆华王雪锋郭尔佳谷林 Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of ScienceBeijing 100049China Beijing National Center for Electron Microscopy and Laboratory of Advanced Materials Department of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Department of Physics&Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Phase transitions involving oxygen ion extraction within the framework of the crystallographic relevance have been widely exploited for sake of superconductivity,ferromagnetism,and ion conductivity in perovskiterelated oxides.However,atomic-scale pathways of phase transitions and ion extraction threshold are inadequately understood.Here we investigate the atomic structure evolution of LaCoO_(3) films upon oxygen extraction and subsequent Co migration,focusing on the key role of epitaxial strain.The brownmillerite to Ruddlesden-Popper phase transitions are discovered to stabilize at distinct crystal orientations in compressive-and tensile-strained cobaltites,which could be attributed to in-plane and out-of-plane Ruddlesden-Popper stacking faults,respectively.A two-stage process from exterior to interior phase transition is evidenced in compressive-strained LaCoO_(2.5),while a single-step nucleation process leaving bottom layer unchanged in tensile-strained situation.Strain analyses reveal that the former process is initiated by an expansion in Co layer at boundary,whereas the latter one is associated with an edge dislocation combined with antiphase boundary.These findings provide a chemomechanical perspective on the structure regulation of perovskite oxides and enrich insights into strain-dependent phase diagram in epitaxial oxides films.

关键词： strained Phase oxides

在线全文

学校读者我要写书评

暂无评论

钴氧化物中晶格与自旋的关联耦合效应研究

物理学报 2023年第9期72卷 33-50页

作者：陈盛如林珊洪海涛崔婷金桥王灿金奎娟郭尔佳中国科学院物理研究所北京凝聚态物质科学国家研究中心北京100190 中国科学院大学物理科学学院和材料与光电研究中心北京100049 橡树岭国家实验室材料科学与技术分部橡树岭37831 松山湖材料实验室东莞523808

强关联电子体系具有多序参量耦合且极易受到外场高效调控的特性.钴氧化物(LaCoO3)是一类典型的多铁性(兼具铁弹性和铁磁性)氧化物材料,受到了研究者们广泛和深入的研究.过去,针对钴氧化物的研究都集中于应力作用下的铁弹性相变和结构调... 详细信息

强关联电子体系具有多序参量耦合且极易受到外场高效调控的特性.钴氧化物(LaCoO3)是一类典型的多铁性(兼具铁弹性和铁磁性)氧化物材料,受到了研究者们广泛和深入的研究.过去,针对钴氧化物的研究都集中于应力作用下的铁弹性相变和结构调控方面.近年来,研究人员新奇地发现钴氧化物薄膜在张应力作用下发生顺磁到铁磁相转变,但其根源一直存在较大争议.部分实验证据表明应力将会导致钴离子价态降低产生自旋态转变,而另一些研究者认为应力诱导的纳米畴结构会呈现高自旋态的长程有序排列,才是钴氧化物薄膜铁磁性的主要原因.本综述主要介绍近几年来钴氧化物薄膜和异质结中自旋与晶格之间关联耦合效应的系列进展.在保持钴离子价态不变时,通过薄膜厚度、晶格失配应力、晶体对称性、表面形貌、界面氧离子配位和氧八面体倾转等结构因素诱导钴氧化物薄膜的自旋态可逆转变,从而形成高度可调的宏观磁性.进而,研究者们利用原子级精度可控的薄膜生长技术构筑了单原胞层钴氧化物超晶格,通过高效的结构调控,实现了超薄二维磁性氧化物材料.这些系列进展不仅澄清了强关联电子体系中晶格与自旋等序参量之间的强耦合关系,而且为实现氧化物自旋电子器件所需的超薄室温铁磁材料提供了优良的候选者.

关键词：铁磁氧化物晶格畸变极化中子反射自旋态转变铁弹相变

外场对拓扑相变氧化物薄膜物性的调控研究进展

在线全文

学校读者我要写书评

暂无评论

物理学报 2023年第9期72卷 2-11页

作者：孙雨婷李明明王玲瑞樊贞郭尔佳郭海中郑州大学物理学院(微电子学院) 郑州450052 华南师范大学华南先进光电子研究院广州510006 中国科学院物理研究所北京凝聚态物理国家研究中心北京100190

钙钛矿型过渡金属氧化物在外场激励下可以通过得失氧离子发生显著的结构拓扑相变,同时伴随着输运、磁性、光学等物性的巨大变化,是近年来被重点关注的研究体系,在固态氧化物燃料电池、氧气传感器、催化活性、智能光学窗口以及神经形态... 详细信息

钙钛矿型过渡金属氧化物在外场激励下可以通过得失氧离子发生显著的结构拓扑相变,同时伴随着输运、磁性、光学等物性的巨大变化,是近年来被重点关注的研究体系,在固态氧化物燃料电池、氧气传感器、催化活性、智能光学窗口以及神经形态计算器件中具有巨大的应用前景.本工作回顾了近年来国内外研究小组在拓扑相变氧化物薄膜及其物性调控方面的工作进展,详细介绍了这类典型薄膜材料在应力场、电场、光场、温度场等外场激励下呈现出的新奇物性,并讨论了其基本物理机制.本综述旨在进一步认识此类材料中的电荷、晶格、轨道等量子序之间的微观耦合机制及其与宏观物性的关联,相关研究有望为基于功能氧化物的高灵敏度、弱场响应的电子器件提供新材料、新途径和新思路.

关键词：拓扑结构相变氧化物薄膜氧空位外场调控

在线全文

学校读者我要写书评

暂无评论

中子散射在磁性材料研究中的应用

物理 2019年第11期48卷 708-714页

作者：郭尔佳朱涛中国科学院物理研究所北京凝聚态物理研究中心

中子具有天然磁矩,穿透能力强且对轻元素敏感等独特的优势,是目前研究材料中磁结构最有力的工具。发展中子散射技术对开发新型磁性材料和研究磁性物理机理等方面具有重大意义。文章介绍了几种常用的中子散射技术(如粉末衍射、小角散射... 详细信息

中子具有天然磁矩,穿透能力强且对轻元素敏感等独特的优势,是目前研究材料中磁结构最有力的工具。发展中子散射技术对开发新型磁性材料和研究磁性物理机理等方面具有重大意义。文章介绍了几种常用的中子散射技术(如粉末衍射、小角散射、反射等),并通过典型的实例来说明它们在磁性材料研究中的具体应用。针对国内介绍中子反射技术的资料相对较少,尤其是极化中子反射技术在精确定量表征薄膜磁性大小和分布方面的研究极度匮乏的现状,文章重点介绍了这一特色技术以及应用实例。

关键词：磁性材料中子散射极化中子反射薄膜与异质结

Photoelectric property of LaAlO_(3-δ)/Si heterojunctions with different oxygen contents

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2011年第3期20卷 398-401页

作者：邢杰郭尔佳温娟 School of Materials Sciences and Technology China University of Geosciences Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences

Three oxide heterojunctions made of LaAlO3-δ/Si are fabricated under various oxygen pressures by laser molecular-beam epitaxy. They all show nonlinear and rectifying current-voltage characteristics, and the distinct difference in rectification behaviour among them. Their photoelectric properties are examined by a visible HeNe laser and an ultraviolet Hg lamp. We find that their photovoltaic responses are closely related to the oxygen contents in the LaAlO3-δ films. The junction fabricated under the lower oxygen pressure has a higher photovoltaic sensitivity. The possible mechanism is suggested based on the band structure of the p-n heterojunction.

关键词： photoelectric heterojunction film

Photon-interactions with perovskite oxides

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2022年第8期31卷 82-94页

作者：姚洪宝郭尔佳葛琛王灿杨国桢金奎娟 Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Songshan Lake Materials Laboratory Dongguan 523808China

Photons with variable energy, high coherency, and switchable polarization provide an ideal tool-kits for exploring the cutting-edge scientific questions in the condensed matter physics and material sciences. Over decades, extensive researches in the sample fabrication and excitation have employed the photon as one of the important means to synthesize and explore the low-dimensional quantum materials. In this review, we firstly summarize the recent progresses of the state-of-the-art thin-film deposition methods using excimer pulsed laser, by which syntactic oxides with atomic-unit-cell-thick layers and extremely high crystalline quality can be programmatically fabricated. We demonstrate that the artificially engineered oxide quantum heterostructures exhibit the unexpected physical properties which are absent in their parent forms. Secondly, we highlight the recent work on probing the symmetry breaking at the surface/interface/interior and weak couplings among nanoscale ferroelectric domains using optical second harmonic generation. We clarify the current challenges in the insitu characterizations under the external fields and large-scale imaging using optical second harmonic generation. The improvements in the sample quality and the non-contact detection technique further promote the understanding of the mechanism of the novel properties emerged at the interface and inspire the potential applications, such as the ferroelectric resistive memory and ultrahigh energy storage capacitors.

关键词： laser molecular-beam epitaxy optical second harmonic generation functional oxides

SrCoO3-x薄膜中氧空位引起的电子结构演变（英文）

在线全文

学校读者我要写书评

暂无评论

Science China Materials 2019年第8期62卷 1162-1168页

作者：赵佳丽罗毅王嘉鸥钱海杰刘晨何旭张庆华黄河意张兵兵李顺芳郭尔佳葛琛杨铁莹李晓龙何萌谷林金奎娟奎热西·依布拉欣郭海中 Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China School of Physical Engineering Zhengzhou University Zhengzhou 450001 China Physique Theorique des Materiaux Q-MAT CESAM University de Liege B-4000 Liege Belgium Institute of Physics Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China Shanghai Synchrotron Radiation Facility (SSRF) Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201204 China

离子缺陷,比如氧空位,在过渡金属氧化物的磁性和电子结构中起着至关重要的作用.对氧空位进行调控广泛应用于催化和能量转换领域.我们研究了SrCoO3-x的电子结构与氧含量x的关系,发现随着氧空位含量的减少, Co 3d和O 2p之间的杂化增强.SrC... 详细信息

离子缺陷,比如氧空位,在过渡金属氧化物的磁性和电子结构中起着至关重要的作用.对氧空位进行调控广泛应用于催化和能量转换领域.我们研究了SrCoO3-x的电子结构与氧含量x的关系,发现随着氧空位含量的减少, Co 3d和O 2p之间的杂化增强.SrCoO2.5+δ的价带顶具有明显的O 2p特征.随着氧含量的进一步增加, Co离子从高自旋的Co3+变成了中自旋的Co4+,实现了绝缘体到金属的转变.关于SrCoO3-x中氧空位引起电子结构演变的研究不仅展示了Co离子自旋的转变,同时也为其在催化和能源领域的应用提供了理论支持.

关键词：电子结构结构演变氧空位过渡金属氧化物薄膜离子缺陷高自旋能量转换

Ultraviolet Sensitive Ultrafast Photovoltaic Effect in Tilted KTaO3 Single Crystals

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2010年第2期27卷 250-252页

作者：邢杰郭尔佳金奎娟吕惠宾何萌温娟杨芳 School of Materials Sciences and Technology China University of Geosciences Beijing 100083 Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190

紫外敏感 ultrafast 光电的效果被观察在倾斜了 10 ? 铼？？

关键词：光电效应紫外线单晶敏感上升时间电压灵敏度电流灵敏度光电脉冲

A synaptic transistor with NdNiO3

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第9期29卷 31-35页

作者：汪翔葛琛李格郭尔佳何萌王灿杨国桢金奎娟 Institute of Physics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Songshan Lake Materials Laboratory Dongguan 523808China

Recently, neuromorphic devices for artificial intelligence applications have attracted much attention. In this work, a three-terminal electrolyte-gated synaptic transistor based on NdNiO3 epitaxial films, a typical correlated electron material, is presented. The voltage-controlled metal-insulator transition was achieved by inserting and extracting H+ ions in the NdNiO3 channel through electrolyte gating. The non-volatile conductance change reached 104 under a 2 V gate voltage. By manipulating the amount of inserted protons, the three-terminal NdNiO3 artificial synapse imitated important synaptic functions, such as synaptic plasticity and spike-timing-dependent plasticity. These results show that the correlated material NdNiO3 has great potential for applications in neuromorphic devices.

关键词： synaptic transistor electrolyte gating artificial synapse NdNiO3 pulsed laser deposition