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1.
E. Takayama-Muromachi T. Drezen N.D. Zhigadlo Y. Matsui 《Journal of solid state chemistry》2003,175(2):366-371
New phases Sr8ARe3Cu4O24 (A=Sr,Ca) were discovered under high-pressure/high-temperature condition. X-ray powder diffraction and electron diffraction studies for these phases indicated that they have an ordered perovskite-type structure with cubic lattices of ∼8 Å. They showed ferromagnetism at room temperature when they were synthesized under high-oxygen-pressure condition. The Ca-containing phase has a very high Tc of 440 K with a spontaneous magnetization of ∼1 μB/f.u. 相似文献
2.
E.Z. Kurmaev G.T. Woods N.D. Zhigadlo E. Takayama-Muromachi D.L. Ederer 《Journal of solid state chemistry》2003,170(1):188-191
Non-resonant V L2,3 and OKα X-ray emission spectra of a new series of (Cu,V)Sr2Can−1CunOy (n=3-7) superconductors are presented. We have found that oxygen atoms surround V-atoms in the given compounds, form a (VO4)3− tetrahedrons and have a pentavalent state. This induces holes due to the substitution of divalent copper by pentavalent vanadium ions providing a hole-doping mechanism of superconductivity in this series of compounds. A spectral estimation of the oxygen concentration shows that the oxygen content under high-pressure/high-temperature synthesis conditions is not changed considerably from the start to the final product. 相似文献
3.
HRTEM study of new series of oxycarbonitrate superconductors (Cu,C,N)Sr2Ca(n - 1)Cu(n)O(y) (n = 1-6)
Anan Y Asaka T Hatano J Zhigadlo ND Takayama-Muromachi E Kimoto K Matsui Y 《Journal of electron microscopy》2001,50(6):457-463
Arrangements of Cu and anion groups (CO3 and NO3) in the charge-reservoir (CR) blocks of a series of new oxycarbonitrate superconductors (Cu,C,N)Sr2Ca(n - 1)Cu(n)O(y) (n = 1-6) were examined by means of electron diffraction and high-resolution transmission electron microscopy (HRTEM). The first three members with n = 1-3 [Tc = 33 K (n = 1), 91 K (n = 2), 90 K (n = 3)] show the 4a0-type superstructures with periodic arrangements, [-Cu-X-X-X-Cu-X-X-X-Cu-] (X = CO3, NO3), in the CR blocks. The third member (n = 3) partly contains the 2a0-type of superstructure with [-Cu-X-Cu-X-Cu] in the CR blocks. The fourth member with n = 4 (Tc = 113 K) contains only the 2a0-type of superstructure. The higher members, with n = 5 (Tc = 65 K) and n = 6 (Tc = 52 K), show no evidence of ordering in the CR blocks, suggesting random arrangements of Cu and anion groups. 相似文献
4.
Kondo T Khasanov R Karpinski J Kazakov SM Zhigadlo ND Bukowski Z Shi M Bendounan A Sassa Y Chang J Pailhés S Mesot J Schmalian J Keller H Kaminski A 《Physical review letters》2010,105(26):267003
We have investigated the electronic states in quasi-one-dimensional CuO chains by microprobe angle resolved photoemission spectroscopy. We find that the quasiparticle Fermi surface consists of six disconnected segments, consistent with recent theoretical calculations that predict the formation of narrow, elongated Fermi surface pockets for coupled CuO chains. In addition, we find a strong renormalization effect with a significant kink structure in the band dispersion. The properties of this latter effect [energy scale (~40 meV), temperature dependence, and behavior with Zn-doping] are identical to those of the bosonic mode observed in CuO2 planes of high-temperature superconductors, indicating they have a common origin. 相似文献
5.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献
6.
JETP Letters - Using multiple Andreev reflections (MAR) effect spectroscopy of SnS junctions, we directly determine temperature dependences of the superconducting order parameters, excess Andreev... 相似文献
7.
L. Ya. Vinnikov T. M. Artemova I. S. Veshchunov N. D. Zhigadlo J. Karpinski P. Popovich D. L. Sun C. T. Lin A. V. Boris 《JETP Letters》2009,90(4):299-302
The vortex structure in the iron pnictide single crystals Ba1?x K x Fe2As2 and Sr1?x K x Fe2As2 of the 122 type and SmFeAsO1?x F x of the 1111 type has been investigated using the decoration method. In all of the crystals under investigation, no regular vortex lattice has been revealed in the magnetic field range up to 200 Oe. The disordered vortex structure is discussed in view of the vortex pinning in single crystals. 相似文献
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9.
We studied SNS and S-N-S-N-...-S contacts (where S is a superconductor and N is a normal metal) formed by “break-junction” technique in polycrystalline Sm1 ? x Th x OFeAs superconductor samples with critical temperatures T C = 34–45 K. In such contacts (intrinsic) multiple Andreev reflections effects were observed. Using spectroscopies based on these effects, we detected two independent bulk order parameters and determined their magnitudes. Theoretical analysis of the large and the small gap temperature dependences revealed superconducting properties of Sm1 ? x Th x OFeAs to be driven by intraband coupling, and $\sqrt {V_{11} V_{22} } /V_{12} \approx 14$ (where V ij are the electron-boson interaction matrix elements), whereas the ratio between density of states for the bands with the small and the large gap, N 2/N 1, correspondingly, was roughly of an order. We estimated “solo” BCS-ratio values in a hypothetic case of zero interband coupling (V i ≠ j = 0) for each condensate as 2ΔL, S/k B T C L,S ≤ 4.5. The values are constant within the range of critical temperatures studied, and correspond to a case of strong intraband electron-phonon coupling. 相似文献
10.
N.D Zhigadlo 《Journal of solid state chemistry》2003,170(1):24-29
New phase (Nd,Ce)2+xCaCu2O6+y was prepared at a high-pressure/high-temperature condition of 6 GPa and 1300°C. It had a nonstoichiometric composition close to Nd2.16Ce0.225CaCu2O6+y. According to X-ray diffraction pattern, the Nd2.16Ce0.225CaCu2O6+y phase has a tetragonal lattice with a = 3.845(1) Å, c = 19.349(5) Å. However, electron microscopic observations revealed a complicated shear structure for this phase. Magnetic susceptibility and magnetic hysteresis measurements were performed for the Nd2.16Ce0.225CaCu2O6+y sample and it was found that the phase undergoes a weak ferromagnetic transition at 150 K. Below ≈40 K, complicated magnetic behavior was observed suggesting the presence of second weak ferromagnetic transition near 40 K. 相似文献