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Electronic Phase Separation in Iron Selenide(Li,Fe)OHFeSe Superconductor System 被引量:1
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作者 Yiyuan Mao Jun Li +14 位作者 Yulong Huan Jie Yuan Zi-an Li Ke Chai Mingwei Ma Shunli Ni Jinpeng Tian Shaobo Lin Huaxue Zhou Fang Zhoul, Jianqi Lil, Guangming Zhang Kui Jin Xiaoli Dong Zhongxian Zhao 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第5期123-128,共6页
The phenomenon of phase separation into antiferromagnetic(AFM) and superconducting(SC) or normal-state regions has great implication for the origin of high-temperature(high-T_c) superconductivity. However, the o... The phenomenon of phase separation into antiferromagnetic(AFM) and superconducting(SC) or normal-state regions has great implication for the origin of high-temperature(high-T_c) superconductivity. However, the occurrence of an intrinsic antiferromagnetism above the T_c of(Li,Fe)OHFe Se superconductor is questioned. Here we report a systematic study on a series of(Li,Fe)OHFe Se single crystal samples with T_c up to ~41 K. We observe an evident drop in the static magnetization at T_(afm) ~ 125 K, in some of the SC(T_c 38 K, cell parameter c■9.27 ?) and non-SC samples. We verify that this AFM signal is intrinsic to(Li,Fe)OHFe Se. Thus, our observations indicate mesoscopic-to-macroscopic coexistence of an AFM state with the normal(below T_(afm)) or SC(below T_c) state in(Li,Fe)OHFe Se. We explain such coexistence by electronic phase separation, similar to that in high-T_c cuprates and iron arsenides. However, such an AFM signal can be absent in some other samples of(Li,Fe)OHFe Se, particularly it is never observed in the SC samples of T_c 38 K, owing to a spatial scale of the phase separation too small for the macroscopic magnetic probe. For this case, we propose a microscopic electronic phase separation. The occurrence of two-dimensional AFM spin fluctuations below nearly the same temperature as T_(afm), reported previously for a(Li,Fe)OHFe Se(T_c ~ 42 K) single crystal, suggests that the microscopic static phase separation reaches vanishing point in high T_c(Li,Fe)OHFe Se. A complete phase diagram is thus established. Our study provides key information of the underlying physics for high-T_c superconductivity. 展开更多
关键词 Li Fe)OHFeSe Superconductor System FE Electronic Phase Separation in Iron Selenide AFM
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Synthesis of large FeSe superconductor crystals via ion release/introduction and property characterization 被引量:1
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作者 苑冬娜 黄裕龙 +8 位作者 倪顺利 周花雪 毛义元 胡卫 袁洁 金魁 张广铭 董晓莉 周放 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第7期93-96,共4页
Large superconducting Fe Se crystals of(001) orientation have been prepared via a hydrothermal ion release/introduction route for the first time. The hydrothermally derived Fe Se crystals are up to 10 mm×5 mm&#... Large superconducting Fe Se crystals of(001) orientation have been prepared via a hydrothermal ion release/introduction route for the first time. The hydrothermally derived Fe Se crystals are up to 10 mm×5 mm×0.3 mm in dimension. The pure tetragonal FeSe phase has been confirmed by x-ray diffraction(XRD) and the composition determined by both inductively coupled plasma atomic emission spectroscopy(ICP-AES) and energy dispersive x-ray spectroscopy(EDX). The superconducting transition of the Fe Se samples has been characterized by magnetic and transport measurements. The zero-temperature upper critical field H(c2) is calculated to be 13.2–16.7 T from a two-band model. The normal-state cooperative paramagnetism is found to be predominated by strong spin frustrations below the characteristic temperature T(sn), where the Ising spin nematicity has been discerned in the FeSe superconductor crystals as reported elsewhere. 展开更多
关键词 FeSe superconductor hydrothermal growth via ion release/introduction upper critical field spin frustrations
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Effect of Mn substitution on superconductivity in iron selenide (Li, Fe)OHFeSe single crystals
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作者 Yiyuan Mao Zian Li +12 位作者 Huaxue Zhou Mingwei Ma Ke Chai Shunli Ni Shaobo Liu Jinpeng Tian Yulong Huang Jie Yuan Kui Jin Xiaoli Dong Fang Zhou Jianqi Li ZhongxianZhao 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第7期492-496,共5页
We synthesize a series of Mn substituted (Li, Fe)OHFeSe superconductor single crystals via a modified ion-exchange method, with the Mn concentration z (the atomic ratio of Mn:Se) ranging from 0 to 0.07. The distr... We synthesize a series of Mn substituted (Li, Fe)OHFeSe superconductor single crystals via a modified ion-exchange method, with the Mn concentration z (the atomic ratio of Mn:Se) ranging from 0 to 0.07. The distribution homogeneity of the Mn element incorporated into the lattice of (Li, Fe)OHFeSe is checked by combined measurements of high-angle- annular-dark-field (HAADF) imaging and electron energy-loss spectroscopy (EELS). Interestingly, we find that the superconducting transition temperature Tc and unit cell parameter c of the Mn-doped (Li, Fe)OHFeSe samples display similar V-shaped evolutions with the increasing dopant concentration z. We propose that, with increasing doping level, the Mn dopant first occupies the tetrahedral sites in the (Li, Fe)OH layers before starting to substitute the Fe element in the su- perconducting FeSe layers, which accounts for the V-shaped change in cell parameter c. The observed positive correlation between the Tc and lattice parameter c, regardless of the Mn doping level z, indicates that a larger interlayer separation, or a weaker interlayer coupling, is essential for the high-Tc superconductivity in (Li, Fe)OHFeSe. This agrees with our previous observations on powder, single crystal, and film samples of (Li, Fe)OHFeSe superconductors. 展开更多
关键词 FeSe-based superconductors Mn doping effect correlation between superconductivity and interlayer separation
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Superconducting (Li,Fe)OHFeSe Film of High Quality and High Critical Parameters
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作者 黄裕龙 冯中沛 +11 位作者 倪顺利 李军 胡卫 刘少博 毛义元 周花雪 周放 金魁 王华兵 袁洁 董晓莉 赵忠贤 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第7期242-245,共4页
A superconducting film of (Li1-xFex)OHFeSe is reported for the first time. The thin film exhibits a small in-plane crystal mosaic of 0.22°, in terms of the full width at half maximum of the x-ray rocking curve,... A superconducting film of (Li1-xFex)OHFeSe is reported for the first time. The thin film exhibits a small in-plane crystal mosaic of 0.22°, in terms of the full width at half maximum of the x-ray rocking curve, and an excellent out-of-plane orientation by x-ray φ-scan. Its bulk superconducting transition temperature Tc of 42.4 K is characterized by both zero electrical resistance and diamagnetization measurements. The upper critical field Hc2 is estimated to be 79.5 T and 443 T for the magnetic field perpendicular and parallel to the ab plane, respectively. Moreover, a large critical current density Jc of a value over 0.5 MA/cm2 is achieved at-20 K. Such a (Li1-xFex)OHFeSe film is therefore not only important to the fundamental research for understanding the high-Tc mechanism, but also promising in the field of high-To superconductivity application, especially in high-performance electronic devices and large scientific facilities such as superconducting accelerator. 展开更多
关键词 SUPERCONDUCTING FE
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Doping Mn into(Li_(1-x)Fe_x)OHFe_(1-y)Se superconducting crystals via ion-exchange and ion-release/introduction syntheses
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作者 周花雪 倪顺利 +10 位作者 袁洁 李军 冯中沛 江星宇 黄裕龙 刘少博 毛义元 周放 金魁 董晓莉 赵忠贤 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第5期1-5,共5页
We report the success in introducing Mn into(Li1-xFex)OHFe1-y Se superconducting crystals by applying two different hydrothermal routes, ion exchange(1-step) and ion release/introduction(2-step). The micro-regio... We report the success in introducing Mn into(Li1-xFex)OHFe1-y Se superconducting crystals by applying two different hydrothermal routes, ion exchange(1-step) and ion release/introduction(2-step). The micro-region x-ray diffraction and energy dispersive x-ray spectroscopy analyses indicate that Mn has been doped into the lattice, and its content in the 1-step fabricated sample is higher than that in the 2-step one. Magnetic susceptibility and electric transport properties reveal that Mn doping influences little on the superconducting transition, regardless of 1-step or 2-step routes. By contrast, the characteristic temperature T^*, at which the negative Hall coefficient reaches its minimum, is significantly reduced by Mn doping.This implies that the hole carriers contribution is obviously modified, and hence the hole band might have no direct relationship with the superconductivity in(Li1-xFex)OHFe1-y Se superconductors. Our present hydrothermal methods of ion exchange and ion release/introduction provide an efficient way for elements substitution/doping into(Li1-xFex)OHFe1-y Se superconductors, which will promote the in-depth investigations on the role of multiple electron and hole bands and their interplay with the high-temperature superconductivity in the FeSe-based superconductors. 展开更多
关键词 hydrothermal doping substitution superconductor bands regardless implies dispersive applying susceptibility
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