共查询到20条相似文献,搜索用时 31 毫秒
1.
Y. Kawashima K. Ichimura J. Ishioka T. Kurosawa M. Oda K. Yamaya S. Tanda 《Physica B: Condensed Matter》2012,407(11):1796-1798
We report the STM study on a single-crystalline sample of FeTe at 7.8 K. FeTe is one of the iron-based superconductor. We measured the resistivity and the magnetization of FeTe. FeTe shows SDW transition at 58 K on these measurements. We study the electronic state of FeTe by using STM/STS for observing FeTe from a microscopic viewpoint. We observed the iron layer and the tellurium layer with atomic resolution. Moreover, we discover the charge stripe structure on STM/STS measurement. We find the charge stripe structure is caused by iron atoms from the analysis. The gap structure of 9 meV was observed in tunneling spectra. This gap size is consistent with the SDW gap which is expected from mean field theory with TN=58 K. 相似文献
2.
自旋转向相变中的条纹磁畴研究 总被引:1,自引:0,他引:1
用光激发电子显微镜研究了Fe/Ni铁磁膜和Co/Cu/Fe/Ni磁耦合膜中的条纹磁畴.实验发现:在Fe/Ni体系中,条纹磁畴宽度随着铁层厚度趋近于自旋转向相变点呈指数下降;在Co/Cu/Fe/Ni体系中,Fe/M层中的条纹磁畴会沿着钴层磁矩的方向排列,其磁畴宽度会随着Co-Fe/Ni间的层间耦合强度呈指数下降.理论上推导出条纹磁畴随着磁各向异性能和层间耦合强度变化的统一公式,而实验结果与理论符合得非常好。 相似文献
3.
S. I. Matveenko 《JETP Letters》2003,78(6):384-388
We show that many observable properties of high-temperature superconductors can be obtained in the framework of a one-dimensional self-consistent model with included superconducting correlations. Analytical solutions for spin, charge, and superconductivity order parameters are found. The ground state of the model at low hole doping is a spin-charge solitonic superstructure. Increased doping leads to a transition to the superconducting phase. There is a region of doping where superconductivity, spin density wave, and charged stripe structure coexist. The charge density modulation appears in the vicinity of vortices (kinks in the 1D model) in the superconducting state. 相似文献
4.
Korobov A. I. Kokshaiskii A. I. Shirgina N. V. Odina N. I. Agafonov A. A. Rzhevskii V. V. 《Technical Physics》2020,65(6):914-920
Technical Physics - The shear elastic properties of YBa2Cu3O7 –x high-temperature superconducting (HTSC) ceramics are studied near the superconducting transition at a temperature of 91.3 K... 相似文献
5.
A comparative study is made for the spin and charge structure around superconducting vortices and unitary impurities, by solving self-consistently an effective Hamiltonian including interactions for both antiferromagnetic spin-density wave (SDW) and d-wave superconducting orderings. Around vortices, we show the induction of an SDW two-dimensionally modulated with a period of eight lattice constants (8a(0)) and an associated charge-density wave (CDW) with a period of 4a(0), which explains very well recent experimental observations. In the case of unitary impurities, an SDW modulation with identical periodicity, but without an associated CDW, is also predicted. 相似文献
6.
《Physics letters. A》1987,123(1):34-36
The superconducting transition temperatures of a family of YBaCu oxides have been explored by dc resistivity measurements. Substitutions of magnetic and non-magnetic ions on Y, Ba and Cu sites are reported. For some compositions, achieving high superconducting transition temperatures is strongly dependent on growth conditions for the material. 相似文献
7.
We report simultaneous NMR and electrical transport experiments in the pressure range near the boundary of the antiferromagnetic spin density wave (SDW) insulator and the metallic/superconducting (SC) phase in (TMTSF)2PF6. Measurements indicate a tricritical point separating a line of second-order SDW/metal transitions from a line of first-order SDW/metal(SC) transitions with coexistence of macroscopic regions of SDW and metal(SC) order, with little mutual interaction but strong hysteretic effects. NMR results quantify the fraction of each phase. 相似文献
8.
Drew AJ Lee SL Charalambous D Potenza A Marrows C Luetkens H Suter A Prokscha T Khasanov R Morenzoni E Ucko D Forgan EM 《Physical review letters》2005,95(19):197201
Superconducting and magnetic order are usually mutually exclusive, and are found to coexist in relatively few materials. We have obtained direct evidence for a spin-density wave (SDW) coexisting with bulk superconductivity in a ferromagnetic-superconducting trilayer. In the superconducting state the amplitude of the SDW is enhanced and modeling the data also suggests a pi/2 phase shift of one component of the SDW, implying a profound coupling of these two forms of order. 相似文献
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10.
Using self-flux method,we have successfully grown the parent phase of the single crystals of CaFeAsF1-x.The X-ray di?raction indicates good crystallinity.In-plane resistivity shows a bad metallic behavior with a sharp drop of resistivity at about T SDW=119K.This anomaly is associated with the possible spin density wave(SDW)order.Interestingly near T SDW,the resistivity exhibits a cusp-like feature,which may be understood as the strong coupling effect between the electrons and the antiferromagnetic(AF)spin fluctuations.A reduction of fluorine or application of a high pressure will suppress the SDW feature and induce superconductivity.Hall effect measurements reveal a positive Hall coefficient below T SDW indicating a dominant role of the hole-like charge carriers in the parent phase.Strong magnetoresistance has been observed below T SDW suggesting multiple conduction channels of the charge carriers. 相似文献
11.
利用射频磁控共溅射方法,在Si衬底上制备了Ni88Cu12薄膜,并且研究了膜厚以及真空磁场热处理温度对畴结构和磁性的影响. X射线衍射结果表明热处理后的薄膜晶粒长大,扫描电子显微镜结果发现不同热处理温度下薄膜表现出不同的形貌特征.热处理前后的薄膜面内归一化磁滞回线结果显示,经过热处理的Ni88Cu12薄膜条纹畴形成的临界厚度降低,未热处理的Ni88Cu12薄膜在膜厚为210 nm时出现条纹畴结构,而经过300℃热处理的Ni88Cu12薄膜在膜厚为105 nm就出现了条纹畴结构.高频磁谱的结果表明,随着热处理温度的增加, Ni88Cu12薄膜的共振峰会有小范围的移动. 相似文献
12.
Korobov A. I. Kokshaysky A. I. Shirgina N. V. Odina N. I. Agafonov A. A. Rzhevsky V. V. 《Acoustical Physics》2019,65(6):658-664
Acoustical Physics - The article presents the results of studies of the elastic properties of the YBa2Cu3O(7 –x) high-temperature superconducting ceramic in the vicinity of the phase... 相似文献
13.
Copper oxides become superconductors rapidly upon doping with electron holes, suggesting a fundamental pairing instability. The Cooper mechanism explains normal superconductivity as an instability of a fermi-liquid state, but high-temperature superconductors derive from a Mott-insulator normal state, not a fermi liquid. We show that precocity to pair condensation with doping is a natural property of competing antiferromagnetism and d-wave superconductivity on a singly-occupied lattice, thus generalizing the Cooper instability to doped Mott insulators, with significant implications for the high-temperature superconducting mechanism. 相似文献
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15.
We have performed elastic neutron-scattering measurements on La1.87Sr0.13Cu0.99Fe0.01O4 to study the magnetic impurity effects on the stripe correlations in high-Tc cuprates. Both charge-density-wave (CDW) and spin-density-wave (SDW) orders are observed in the low-temperature-orthorhombic (LTO) phase for the first time. With decreasing the temperature, CDW order first appears at followed by the SDW order at lower temperature of . The incommensurability for the CDW order (ε) was found to be 0.224±0.002 r.l.u., which is approximately twice of that for SDW order (δ) of 0.115±0.003 r.l.u. Both ordering sequence and relation of ε≈2δ are the same for SDW and CDW orders observed in the low-temperature-tetragonal (LTT) phase of La1.60-xNd0.4SrxCuO4 (LNSCO), suggesting that the similar stripe correlations exist in the cuprate oxides, irrespective of crystal structure. 相似文献
16.
We present a review of photoexcited quasiparticle dynamics of cuprate and pnictide high‐temperature superconductors in regimes (temperature, doping) where different phases such as superconductivity, spin‐density‐wave (SDW) and pseudogap phases coexist or compete with one another. We start with the overdoped cuprate superconductor Y1–xCax Ba2Cu3O7–δ, where the superconducting gap and pseudogap coexist in the superconducting state. In another cuprate Tl2Ba2Ca2Cu3Oy, we ob‐ serve a competition between SDW and superconducting orders deep in the superconducting state. Finally, in the underdoped iron pnictide superconductor (Ba,K)Fe2As2, SDW order forms at 85 K, followed by superconductivity at 28 K. We also find the emergence of a normal‐state order that suppresses SDW at a temperature T * ~ 60 K and argue that this normal‐state order is a precursor to superconductivity. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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18.
Copper oxides become superconductors rapidly upon doping with electron holes, suggesting a fundamental pairing instability.
The Cooper mechanism explains normal superconductivity as an instability of a fermi-liquid state, but high-temperature superconductors
derive from a Mott-insulator normal state, not a fermi liquid. We show that precocity to pair condensation with doping is
a natural property of competing antiferromagnetism and d-wave superconductivity on a singly-occupied lattice, thus generalizing the Cooper instability to doped Mott insulators, with
significant implications for the high-temperature superconducting mechanism. 相似文献
19.
Various unconventional isotope effects have been reported in
high-temperature superconducting copper oxides which are beyond the scheme
of BCS theory. Their origin is investigated within polaron theory which
leads to a renormalization of the single particle energies and introduces a
level shift here. It is found that the exponential squeezing of the second
nearest neighbour hopping integral carries the correct isotope effect on the
superconducting transition temperature Tc, as well as the one on the
penetration depth. The average superconducting gap is predicted to have an
isotope effect comparable to the one on the penetration depth. The results
imply that the coupling of the electronic degrees of freedom to the
Jahn-Teller Q2-type mode is the origin of these isotope effects. 相似文献