H. Zhang
Peking University
EpitaxyCrystal structureAnalytical chemistryCupratePhase transitionPerovskite (structure)Bond lengthPlane (geometry)ChemistryThin filmMaterials scienceDiffractionScanning electron microscopeCondensed matter physicsMagnetizationTexture (crystalline)Differential scanning calorimetryThermogravimetrySuperconductivityFlux pinningDopingElectrical resistivity and conductivityCrystallographyMicrostructure
120Publications
16H-index
1,002Citations
Publications 115
Newest
#1Chang Chun Hsieh (Southwest Jiaotong University)H-Index: 2
#2Chuan Ke (Southwest Jiaotong University)H-Index: 5
Last. Yuancong Zhao (Southwest Jiaotong University)H-Index: 17
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Ba2Ti2(Fe1−x Cr x )2As4O (0 ≤ x ≤ 8%) compounds are synthesized by solid-state reaction and their structure and superconductivity are studied with x-ray diffraction, electric resistivity, and magnetization measurements. It is observed that the Cr dopants in the Fe site of Ba2Ti2Fe2As4O expand the lattice constants, but do not cause any structure phase transition. Superconducting transition temperature T c of the Ba2Ti2(Fe1−x Cr x )2As4O is found monotonically depressed with Cr doping level at an...
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#1Chang Chun Hsieh (Southwest Jiaotong University)H-Index: 2
#2Chuan Ke (Southwest Jiaotong University)H-Index: 5
Last. Yuancong Zhao (Southwest Jiaotong University)H-Index: 17
view all 6 authors...
Abstract Chemical doping effects on structure and superconductivity were studied by introducing Cr at Fe sites in Ba 2 Ti 2 Fe 2 As 4 O, where Cr 2+ can play dual role as impurities and hole dopants. Ba 2 Ti 2 (Fe 1-x Cr x ) 2 As 4 O (0 ≤ x ≤ 8%) compounds are synthesized by a solid-state reaction and characterized with x-ray diffraction, electric resistivity and magnetization measurements. It is observed that the Cr dopants induce lattice expansion and local structure distortion, and significan...
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#1Chifei WuH-Index: 20
#2Suzhan ZhangH-Index: 24
Last. Shuying DongH-Index: 30
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Pseudogap is a unique property of high-Tc superconductors. However, it was also found that there is a similar pseudogap in giant magnetoresistive La–Sr–Mn–O materials, which are not superconductors. In our previous research, we suggested that the origin of the pseudogap is correlated with the stability of CuO2 plane. We call it a steady “fixed triangle” local structure. If our assumption is correct, it will be expected to find a similar stable local structure in the La–Sr–Mn–O system, which is s...
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In this paper, we systematically studied Ca–YBCO (Y1−xCaxBa2Cu3O7−δ) and CaLa–YBCO (Y1−xCaxBa2−xLaxCu3O7−δ) systems by Raman spectroscopy. It is found that Tc is closely related to the vibration of lattice. In the Ca–YBCO system, the phonons around 115 and 335 cm−1 harden as the Tc decreases. Oppositely, the 140 cm−1 mode and the 220 cm−1 mode soften. In the CaLa–YBCO system, the Tc decreases gradually with the content of Ca and La. The Raman peak of 140 cm−1 mode hardens and the 360 cm−1 mode s...
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A new structure basis of SmBiO3 (SBO) potential buffer layer for low-cost coated conductors fabrication methods has been introduced in this paper, and studied with XRD, SEM and AFM analyses. It is found that highly in-plane and out-of-plane oriented, dense, smooth, and crack-free SBO buffer layer has been prepared on NiO-buffered Ni-5 %W (NiW) tapes via a CSD route. YBCO epitaxial film was obtained on CSD-YBCO/CSD-SmBiO3/SOE-NiO/NiW by using F-free CSD method which shows a new route to search fo...
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BaZrO3 (BZO) epitaxial films have been deposited on single-crystal substrate by polymer-assisted chemical solution deposition method and have been studied with X-ray diffraction (XRD), SEM, and AFM analyses. It is found that the surface morphology and degree of c-axis texturing of the epi-films vary with processing temperature and atmosphere, with the optimized processing temperature of 900 °C in argon. The films are found with good phase purity, high-degree in-plane and out-of-plane texturing, ...
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Abstract The electronic structure and chemical states of relevant elements of YBa 2 Fe 3 O 8 are investigated using X-ray photoemission spectroscopy (XPS), compared with those of YBa 2 Cu 3 O 7 and SmFeAsO 0.8 F 0.2 superconductors. The typical differences and similarities in core-level and valence-band structures of these systems have been detected, strongly suggesting that the superconductivity have the finite density of states around Fermi level. Several features of O1 s , Y3 d, Ba3 d , and F...
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#1C. Q. Guo (PKU: Peking University)H-Index: 4
#2Xueyan Sun (PKU: Peking University)H-Index: 4
Last. H. Zhang (PKU: Peking University)H-Index: 16
view all 6 authors...
Abstract The compensated systems of Y 1− x Sr x Ba 2− x La x Cu 3 O y were synthesized and characterized by DC magnetization measurements and X-ray diffraction. The structures of the samples were refined by Rietveld method. Although the carrier concentration in the samples is constant at different doping levels, the superconductivity evidently changes. The combinative energy in the system was calculated and it was discovered that the decrease of T c has close relationship with the increase of th...
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Abstract In order to explore how important the electron–phonon coupling is in high T c superconductors, we calculate the phonon frequencies at Gamma-point of the Y x Pr 1− x Ba 2 Cu 3 O 7 system by considering a special local structure in the Y x Pr 1− x Ba 2 Cu 3 O 7 , which is so called “fixed triangle”. It is found that a low frequency mode is possibly caused by the “fixed triangle” and roughly matches the experiment of Raman spectrum, which suggests that the coupling between electron and pho...
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