Antiferromagnetism has become a promising candidate for the next generation electronic devices due to its thermal stability,low energy consumption,and fast switching speed.However,the canceling of the net magnetic mom...Antiferromagnetism has become a promising candidate for the next generation electronic devices due to its thermal stability,low energy consumption,and fast switching speed.However,the canceling of the net magnetic moment in antiferromagnetic order presents great challenge on quantitative characterization and modulation,hindering its investigation and application.In this work,utilizing the optical second harmonic generation(SHG)in a wide temperature range,the integrated differential phase contrast scanning transmission electron microscopy,and firstprinciples calculations,we performed a quantitative study on the evolution of non-collinear antiferromagnetic order in BiFeO_(3)films with a series of strains.We found that the antiferromagnetic coupling was significantly enhanced,featured by the increase of Néel temperature from 428 K to 646 K,and by one order of enhancement of SHG intensity contributed from the G-type antiferromagnetic order by strain manipulation from-2.4%to+0.6%.We attributed the enhancement of the antiferromagnetic coupling to the enhancement of the superexchange interaction as the Fe-O-Fe bond angle approaches 180°when the in-plane lattice constants increase,which might also result in a tendency from a non-collinear antiferromagnetic order to a collinear one.Our work not only bridges the antiferromagnetic order and the strain manipulation in epitaxial multiferroics,more importantly,also paves a way for quantitative characterization by SHG technology and the precise manipulation of antiferromagnetism.展开更多
Highly efficient nonlinear optical（NLO） materials with well-defined architectures in the wavelength and subwavelength length scales are of particular importance for next generation of integrated photonic circuits. F...Highly efficient nonlinear optical（NLO） materials with well-defined architectures in the wavelength and subwavelength length scales are of particular importance for next generation of integrated photonic circuits. Fluorenone analogues have been demonstrated to be promising candidates as building blocks for assembly of organic NLO materials thanks to their synergistic supramolecular interactions and brilliant optical properties. Here we have studied the polymorphs of a phenylethynyl functionalized fluorenone derivative, and their controlled self-assembly for microstructures with different morphologies. These polymorphic microcrystals exhibit very distinctive NLO properties, highly related to their supramolecular and electronic structures.展开更多
A new nonlinear optical crystal of sodium terbium borate （Na2.67Tb2.11B3O9, Mr = 573.14） was synthesized by solid reaction method. The colorless transparent single crystals were grown from the high temperature solut...A new nonlinear optical crystal of sodium terbium borate （Na2.67Tb2.11B3O9, Mr = 573.14） was synthesized by solid reaction method. The colorless transparent single crystals were grown from the high temperature solution by employing NaBO2 as flux. The structure was deter- mined by single-crystal X-ray diffraction method. The compound crystallizes in the orthorhombic system, space group Amm2 with a = 5.0744（10）, b = 10.990（2）, c = 6.9078（14） A, V = 385.24（13） A3, Dc = 4.941 g/cm3, F（000） = 250, Z = 2, μ= 9.205 mm-1, the final R = 0.0253 and wR = 0.0610. Its three-dimensional network structure is constructed from isolated BO33-, Na（1）O8, Na（2）O6, Na（3）O6 and Tb（1）O9 polyhedra. Variable-temperature magnetic susceptibility measurements show the compound is paramagnetic （μj = 7.04 μb）. The intensity of the second harmonic generation of Na2.67Tb2.11B3O9 is 2.5 times that of KDP.展开更多
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 deca...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.展开更多
基金supported by the National Key Basic Research Program of China(Grant No.2019YFA0308500,2020YFA0309100,and 2021YFA1400701)the National Natural Science Foundation of China(Grant No.12174437,No.12222414,No.12074416,and No.12104054)+4 种基金the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB33030200)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.Y2022003)the China Postdoctoral Innovative Talent Support Program(Grant No.BX20240409)the China Postdoctoral Science Foundation(Grant No.2024M763507)the Beijing Natural Science Foundation(Grant No.1222035).
文摘Antiferromagnetism has become a promising candidate for the next generation electronic devices due to its thermal stability,low energy consumption,and fast switching speed.However,the canceling of the net magnetic moment in antiferromagnetic order presents great challenge on quantitative characterization and modulation,hindering its investigation and application.In this work,utilizing the optical second harmonic generation(SHG)in a wide temperature range,the integrated differential phase contrast scanning transmission electron microscopy,and firstprinciples calculations,we performed a quantitative study on the evolution of non-collinear antiferromagnetic order in BiFeO_(3)films with a series of strains.We found that the antiferromagnetic coupling was significantly enhanced,featured by the increase of Néel temperature from 428 K to 646 K,and by one order of enhancement of SHG intensity contributed from the G-type antiferromagnetic order by strain manipulation from-2.4%to+0.6%.We attributed the enhancement of the antiferromagnetic coupling to the enhancement of the superexchange interaction as the Fe-O-Fe bond angle approaches 180°when the in-plane lattice constants increase,which might also result in a tendency from a non-collinear antiferromagnetic order to a collinear one.Our work not only bridges the antiferromagnetic order and the strain manipulation in epitaxial multiferroics,more importantly,also paves a way for quantitative characterization by SHG technology and the precise manipulation of antiferromagnetism.
基金the financial supports from the National Natural Science Foundation of China(NSFC) (Nos.21773168, 51503143 and 21761132007)the Tianjin Natural Science Foundation(No. 16JCQNJC05000)+5 种基金the Innovation Foundation of Tianjin University (No. 2016XRX-0017)the China International Science and Technology Projects(No. S2016G3413)The Netherlands Organization for Scientific Research (NWO) with the Veni Grant (No. 680-47-437)The Royal Netherlands Academy of Arts and Sciences(KNAW) with the China-Exchange Program (No. 530-4CDPO2)the Tianjin 1000 Youth Talents Planthe Chinese Scholarship Council (CSC)
文摘Highly efficient nonlinear optical（NLO） materials with well-defined architectures in the wavelength and subwavelength length scales are of particular importance for next generation of integrated photonic circuits. Fluorenone analogues have been demonstrated to be promising candidates as building blocks for assembly of organic NLO materials thanks to their synergistic supramolecular interactions and brilliant optical properties. Here we have studied the polymorphs of a phenylethynyl functionalized fluorenone derivative, and their controlled self-assembly for microstructures with different morphologies. These polymorphic microcrystals exhibit very distinctive NLO properties, highly related to their supramolecular and electronic structures.
基金supported by the National Natural Science Foundation of China (91022025, 51072036)the Natural Science Foundation of Fujian Province (2010J01284)
文摘A new nonlinear optical crystal of sodium terbium borate （Na2.67Tb2.11B3O9, Mr = 573.14） was synthesized by solid reaction method. The colorless transparent single crystals were grown from the high temperature solution by employing NaBO2 as flux. The structure was deter- mined by single-crystal X-ray diffraction method. The compound crystallizes in the orthorhombic system, space group Amm2 with a = 5.0744（10）, b = 10.990（2）, c = 6.9078（14） A, V = 385.24（13） A3, Dc = 4.941 g/cm3, F（000） = 250, Z = 2, μ= 9.205 mm-1, the final R = 0.0253 and wR = 0.0610. Its three-dimensional network structure is constructed from isolated BO33-, Na（1）O8, Na（2）O6, Na（3）O6 and Tb（1）O9 polyhedra. Variable-temperature magnetic susceptibility measurements show the compound is paramagnetic （μj = 7.04 μb）. The intensity of the second harmonic generation of Na2.67Tb2.11B3O9 is 2.5 times that of KDP.
基金Project supported by the National Key Basic Research Program of China(Grant Nos.2017YFA0303604,2019YFA0308500,and 2020YFA0309100)the National Natural Science Foundation of China(Grant Nos.11721404,11934019,11974390,and 12074416)+3 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2018008)the Beijing Nova Program of Science and Technology(Grant No.Z191100001119112)Beijing Natural Science Foundation(Grant No.2202060)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB33030200)。
文摘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.
