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相关论文: Optical studies of charge dynamics in c-axis orien…

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A large anisotropy in the upper critical field (H$_{C2}$) is observed for MgB$_{2}$ films grown in situ by a pulsed laser deposition process involving growth and annealing of Mg and B multilayers. Measurements of resistivity as a function…

超导电性 · 物理学 2007-05-23 S. R. Shinde , S. B. Ogale , A. Biswas , R. L. Greene , T. Venkatesan

We have measured the resistivity, optical conductivity, and magnetic susceptibility of LaSb$_2$ to search for clues as to the cause of the extraordinarily large linear magnetoresistance and to explore the properties of the superconducting…

强关联电子 · 物理学 2015-05-19 J. F. DiTusa , V. Guritanu , S. Guo , D. P. Young , P. W. Adams , R. G. Goodrich , J. Y. Chan , D. van der Marel

We have measured the frequency and temperature dependences of complex ac conductivity, \sigma(\omega)=\sigma_1(\omega)-i\sigma_2(\omega), of NbN films in zero magnetic field between 0.1 to 10 GHz using a microwave broadband technique. In…

超导电性 · 物理学 2009-11-11 Takeyoshi Ohashi , Haruhisa Kitano , Astutaka Maeda , Hiroyuki Akaike , Akira Fujimaki

We synthesized single crystalline and policrystalline MgB_2 under ambient pressures. The single crystals of MgB_2 were of good quality, where the crystal structure refinements were successfully converged with R = 0.020. The specific heat of…

超导电性 · 物理学 2009-11-07 Y. Machida , S. Sasaki , H. Fujii , M. Furuyama , I. Kakeya , K. Kadowaki

The temperature dependence of the $ab$-plane optical reflectivity of Ba(Fe$_{0.92}$Co$_{0.08})_2$As$_{2}$ and Ba(Fe$_{0.95}$Ni$_{0.05})_2$As$_{2}$ single crystals is measured in a wide spectral range. Upon entering the superconducting…

超导电性 · 物理学 2009-12-07 D. Wu , N. Barisic , N. Drichko , P. Kallina , A. Faridian , B. Gorshunov , M. Dressel , L. J. Li , X. Lin , G. H. Cao , Z. A. Xu

We report the growth and properties of epitaxial MgB2 thin films on (0001) Al2O3 substrates. The MgB2 thin films were prepared by depositing boron films via RF magnetron sputtering, followed by a post-deposition anneal at 850C in magnesium…

We report synthesis, structure/micro-structure, resistivity under magnetic field [R(T)H], Raman spectra, thermoelectric power S(T), thermal conductivity K(T), and magnetization of ambient pressure argon annealed polycrystalline bulk samples…

超导电性 · 物理学 2015-05-13 V. P. S. Awana , Arpita Vajpaye , Monika Mudgel , H. Kishan , V. Ganesan , A. M. Awasthi , G. L. Bhalla

We have measured the longitudinal resistivity and the Hall resistivity in the ab-plane of highly c-axis-oriented MgB2 thin films. In the normal state, the Hall coefficient (R_H) behaves as R_H ~ T with increasing temperature (T) up to 130 K…

超导电性 · 物理学 2009-11-07 W. N. Kang , Hyeong-Jin Kim , Eun-Mi Choi , Heon Jung Kim , Kijoon H. P. Kim , H. S. Lee , Sung-Ik Lee

The Raman spectrum of the superconductor MgB$_{2}$ has been measured as a function of the Tc of the film. A striking correlation is observed between the $T_{c}$ onset and the frequency of the $E_{2g}$ mode. Analysis of the data with the…

超导电性 · 物理学 2009-11-10 K. A. Yates , G. Burnell , N. A. Stelmashenko , D. -J. Kang , H. N. Lee , B. Oh , M. G. Blamire

The anisotropic conductivity of a series of tilted Nd_{1.85}Ce_{0.15}CuO_{4-\delta} thin films was measured by quasioptical spectroscopy in the frequency range 3cm^{-1}<\nu <40cm^{-1}. Two characteristic features have been observed in the…

超导电性 · 物理学 2009-10-31 A. Pimenov , A. V. Pronin , A. Loidl , A. Kampf , S. I. Krasnosvobodtsev , V. S. Nozdrin

The electronic anisotropy in MgB2, is still a not completely clear topic; high quality c-oriented films are suitable systems to investigate this property. In this work we present our results on MgB2 superconducting thin films grown on MgO…

We measured the polarized optical conductivity of URu$_2$Si$_2$ from room temperature down to 5 K, covering the Kondo state, the coherent Kondo liquid regime, and the hidden-order phase. The normal state is characterized by an anisotropic…

强关联电子 · 物理学 2015-08-12 R. P. S. M. Lobo , J. Buhot , M. A. Méasson , D. Aoki , G. Lapertot , P. Lejay , C. C. Homes

Field and temperature microwave measurements have been carried out on MgB2 thin film grown on Al2O3 substrate. The analysis reveals the mean field coherence length xi_{MF} in the mixed state and a temperature independent anisotropy ratio…

超导电性 · 物理学 2009-11-07 A. Dulcic , M. Pozek , D. Paar , Eun-Mi Choi , Hyun-Jung Kim , W. N. Kang , Sung-Ik Lee

Superconducting Pr$_2$CuO$_x$, $x\simeq 4$ films with $T^\prime$ structure and a $T_c$ of 27 K have been investigated by millimeter-wave transmission and broadband (infrared-to-ultraviolet) reflectivity measurements in the normal and…

超导电性 · 物理学 2015-01-12 E. Schachinger , G. Chanda , R. P. S. M. Lobo , M. Naito , A. V. Pronin

The in-plane infrared and visible (3 meV-3 eV) reflectivity of Bi2Sr2CaCu2O8+d (Bi-2212) thin films is measured between 300 K and 10 K for different doping levels with unprecedented accuracy. The optical conductivity is derived through an…

We measured the optical reflectivity of the Dirac material Au$_{2}$Pb in a broad frequency range (30 - 48 000 cm$^{-1}$) for temperatures between 9 and 300 K. The optical conductivity, computed from the reflectivity, is dominated by…

介观与纳米尺度物理 · 物理学 2018-11-14 R. Kemmler , R. Hübner , A. Löhle , D. Neubauer , I. Voloshenko , L. M. Schoop , M. Dressel , A V. Pronin

Observed optical reflectivity in the infrared spectral region is compared with theoretical predictions in a strongly coupled electron-phonon system. Starting from a Froehlich Hamiltonian, the spectral functions and their temperature…

超导电性 · 物理学 2007-05-23 H. J. Kaufmann , E. G. Maksimov , E. K. H. Salje

The dependence of Tc on nearly hydrostatic pressure has been measured for an isotopically pure (11B) MgB2 sample in a helium-loaded diamond-anvil-cell to nearly 20 GPa. Tc decreases monotonically with pressure from 39.1 K at ambient…

超导电性 · 物理学 2009-11-07 S. Deemyad , J. S. Schilling , J. D. Jorgensen , D. G. Hinks

The review considers bulk MgB2-based materials in terms of their structure, superconducting and mechanical properties. Superconducting transition temperatures of 34.5-39.4 K, critical current densities of 1.8-1.0 x E6 A/sq.cm in self field…

超导电性 · 物理学 2009-12-25 T. A. Prikhna

A theory of the frequency dependence of the interplane conductivity of a strongly anisotropic superconductor is presented. The form of the conductivity is shown to be a sensitive probe of the strength of quantum and thermal fluctuations of…

强关联电子 · 物理学 2009-10-31 L. B. Ioffe , A. J. Millis