Two magnetic Gruneisen parameters in the ferromagnetic superconductor UGe
F. Hardy, C. Meingast, V. Taufour, J. Flouquet, H. v. Lohneysen et al.
We report ambient-pressure magnetization, heat capacity, and thermal-expansion measurements of the ferromagnetic superconductor UGe in high magnetic fields. An analysis of the magnetic heat capacity derived from both magnetization and specific-heat data shows that UGe is well described in the framew ... [Phys. Rev. B 80, 174521 (2009)] published Fri Nov 20, 2009.
Model of Quasiparticles Coupled to a Frequency-Dependent Charge-Density-Wave Order Parameter in Cuprate Superconductors
G. Seibold, M. Grilli, and J. Lorenzana
We investigate a model where superconducting electrons are coupled to a frequency dependent charge-density wave order parameter Delta(omega). Our approach can reconcile the simultaneous existence of low-energy Bogoljubov quasiparticles and high energy electronic order as observed in scanning tunneli ... [Phys. Rev. Lett. 103, 217005 (2009)] published Fri Nov 20, 2009.
Flux pinning properties in BaMO (M=Zr,Sn) nanorod-introduced ErBaCuO films
Satoshi Awaji, Masafumi Namba, Kazuo Watnabe, Shun Ito, Eiji Aoyagi et al.
Flux pinning properties on the ErBaCaO films with the nanoscaled and columnar-shaped BaMO (BMO,M=Zr,Sn) precipitates, i.e., nanorods, were investigated systematically based on the microstructure, critical current density J and irreversibility field B properties in high magnetic fields. We found that ... [J. Appl. Phys. 106, 103915 (2009)] published Fri Nov 20, 2009.
Nonperturbative theory of type-II superconductivity in the presence of a strong Pauli paramagnetic effect
V. Zhuravlev and T. Maniv
The unusual low-temperature superconducting (SC) phase transitions following the competition between orbital and spin electron pair breaking, characterizing clean, heavy fermion, strongly type-II superconductors at high magnetic fields, are investigated within a nonperturbaive approach, which enable ... [Phys. Rev. B 80, 174520 (2009)] published Thu Nov 19, 2009.
Scaling of the superfluid density in strongly underdoped YBaCuO: Evidence for a Josephson phase
C. C. Homes
Recent measurements on extremely underdoped YBaCuO [Phys. Rev. Lett. 99, 237003 (2007)] have allowed the critical temperature T, superfluid density rho[equivalent]rho(T<
Local Current Injection into Mesoscopic Superconductors for the Manipulation of Quantum States
M. V. Milosevic, A. Kanda, S. Hatsumi, F. M. Peeters, and Y. Ootuka
We perform strategic current injection in a small mesoscopic superconductor and control the (non)equilibrium quantum states in an applied homogeneous magnetic field. In doing so, we realize a current-driven splitting of multiquanta vortices, current-induced transitions between states with different ... [Phys. Rev. Lett. 103, 217003 (2009)] published Thu Nov 19, 2009.
Photon absorption edge in superconductors and gapped one-dimensional systems
V. V. Mkhitaryan, E. G. Mishchenko, M. E. Raikh, and L. I. Glazman
Opening of a gap in the low-energy excitations spectrum affects the power-law singularity in the photon absorption spectrum A(Omega). In the normal state, the singularity, A(Omega)[proportional][D/(OmegaOmega)], is characterized by an interaction-dependent exponent alpha. On the contrary, in the sup ... [Phys. Rev. B 80, 205416 (2009)] published Wed Nov 18, 2009.
Collective cavity mode excitations in arrays of Josephson junctions
I. Ottaviani, M. Cirillo, M. Lucci, V. Merlo, M. Salvato et al.
We report on oscillations of a Josephson-junction system revealing a close analogy with fundamental effects known in laser physics. The experiments are performed on series arrays of junctions whose IV curves show evidence of a mode in which all the junctions oscillate in synchronism on resonances ap ... [Phys. Rev. B 80, 174518 (2009)] published Wed Nov 18, 2009.
Intrinsic pinning on structural domains in underdoped single crystals of Ba(FeCo)As
R. Prozorov, M. A. Tanatar, N. Ni, A. Kreyssig, S. Nandi et al.
Critical current density was studied in single crystals of Ba(FeCo)As for the values of x spanning the entire doping phase diagram. A noticeable enhancement was found for slightly underdoped crystals with the peak at x=0.058. Using a combination of polarized-light imaging, x-ray diffraction and magn ... [Phys. Rev. B 80, 174517 (2009)] published Wed Nov 18, 2009.
Josephson effects in weakly coupled MgB intergrain nanobridges prepared by focused ion beam
Soon-Gul Lee, Sung-Hak Hong, Won Kyung Seong, and Won Nam Kang
We have fabricated weakly coupled intergrain nanobridges from MgB films by a focused ion beam (FIB) patterning technique and studied their transition properties. The bridges were nominally 300 nm wide and 100 nm long, and crossed a single grain boundary perpendicularly. The temperature-dependent res ... [Appl. Phys. Lett. 95, 202504 (2009)] published Wed Nov 18, 2009.
Theory of small charge solitons in one-dimensional arrays of Josephson junctions
Stephan Rachel and Alexander Shnirman
We identify and investigate the parameter regime of small charge solitons in one-dimensional arrays of Josephson junctions. We obtain the dispersion relation of the soliton and show that it unexpectedly flattens in the outer region of the Brillouin zone. We demonstrate Lorentz contraction of the sol ... [Phys. Rev. B 80, 180508 (2009)] published Tue Nov 17, 2009.
Local density of states and superconducting gap in the iron chalcogenide superconductor FeSeTe observed by scanning tunneling spectroscopy
Takuya Kato, Yoshikazu Mizuguchi, Hiroshi Nakamura, Tadashi Machida, Hideaki Sakata et al.
We report on the investigation of the quasiparticle local density of states and superconducting gap in the iron chalcogenide superconductor FeSeTe(T~14 K). The surface of a cleaved crystal revealed an atomic square lattice, superimposed on the inhomogeneous background, with a lattice constant of ~3 ... [Phys. Rev. B 80, 180507 (2009)] published Tue Nov 17, 2009.
Temperature-dependent critical currents in superconducting YBaCuO and ferromagnetic LaCaMnO hybrid structures
M. Djupmyr, S. Soltan, H.-U. Habermeier, and J. Albrecht
The local critical current density in thin-film hybrid structures of high-temperature superconducting YBaCuO and ferromagnetic LaCaMnO (LCMO) is measured with high accuracy using a quantitative magneto-optical method. The superconducting films are grown onto vicinal cut substrates where step-flow gr ... [Phys. Rev. B 80, 184507 (2009)] published Tue Nov 17, 2009.
Evidence for Two Competing Order Parameters in Underdoped Cuprate Superconductors from a Model Analysis of Fermi-Arc Effects
Andres Greco
Preformed pairs above T and the two-gap scenarios are two main proposals for describing the low-doping pseudogap phase of high-T cuprates. Very recent angle-resolved photoemission experiments have shown features which were interpreted as evidence for preformed pairs. Here it is shown that those resu ... [Phys. Rev. Lett. 103, 217001 (2009)] published Tue Nov 17, 2009.
Differences in the high-energy kink between hole- and electron-doped high-T superconductors
M. Ikeda, T. Yoshida, A. Fujimori, M. Kubota, K. Ono et al.
We have performed an angle-resolved photoemission spectroscopy (ARPES) study of NdCeCuO (NCCO) in order to elucidate the origin of the high-energy kink (HEK) observed in the high-T superconductors (HTSCs). The energy scale of the HEK in NCCO is large compared with that in hole-doped HTSCs, consisten ... [Phys. Rev. B 80, 184506 (2009)] published Mon Nov 16, 2009.
Transverse instabilities of multiple vortex chains in magnetically coupled NbSe/permalloy superconductor/ferromagnet bilayers
G. Karapetrov, M. V. Milosevic, M. Iavarone, J. Fedor, A. Belkin et al.
Using scanning tunneling microscopy and Ginzburg-Landau simulations, we explore vortex configurations in magnetically coupled NbSe/permalloy superconductor/ferromagnet bilayer. The permalloy film with stripe domain structure induces periodic local magnetic induction in the superconductor, creating a ... [Phys. Rev. B 80, 180506 (2009)] published Mon Nov 16, 2009.
Measurement of spin memory lengths in PdNi and PdFe ferromagnetic alloys
H. Z. Arham, Trupti S. Khaire, R. Loloee, W. P. Pratt, Jr., and Norman O. Birge
Weakly ferromagnetic alloys are being used by several groups in the study of superconducting/ferromagnetic hybrid systems. Because spin-flip and spin-orbit scattering in such alloys disrupt the penetration of pair correlations into the ferromagnetic material, it is desirable to have a direct measure ... [Phys. Rev. B 80, 174515 (2009)] published Mon Nov 16, 2009.
Observation of a coherent optical phonon in the iron pnictide superconductor Ba(FeCo)As (x=0.06 and 0.08)
B. Mansart, D. Boschetto, A. Savoia, F. Rullier-Albenque, A. Forget et al.
We report the observation of a coherent lattice oscillation in a pnictide superconductor. A coherent fully symmetric optical phonon was detected in Ba(FeCo)As (x=0.06 and x=0.08) using time-resolved pump-probe reflectivity with 40 fs time resolution. The analysis of the phonon parameters for various ... [Phys. Rev. B 80, 172504 (2009)] published Mon Nov 16, 2009.
Functional renormalization-group study of the doping dependence of pairing symmetry in the iron pnictide superconductors
Ronny Thomale, Christian Platt, Jiangping Hu, Carsten Honerkamp, and B. Andrei Bernevig
We use the functional renormalization group to analyze the phase diagram of a four-band model for the iron pnictides subject to band interactions with certain A momentum dependence. We determine the parameter regimes where an extended s-wave pairing instability with and without nodes emerges. For el ... [Phys. Rev. B 80, 180505 (2009)] published Fri Nov 13, 2009.
Theory of two-dimensional macroscopic quantum tunneling in YBaCuO Josephson junctions coupled to an LC circuit
Shiro Kawabata, Thilo Bauch, and Takeo Kato
We investigate classical thermal activation (TA) and macroscopic quantum tunneling (MQT) for a YBaCuO (YBCO) Josephson junction coupled to an LC circuit theoretically. Due to the coupling between the junction and the LC circuit, the macroscopic phase dynamics can be described as the escape process o ... [Phys. Rev. B 80, 174513 (2009)] published Fri Nov 13, 2009.
Angular dependence of the upper critical field of SrRuO
S. Kittaka, T. Nakamura, Y. Aono, S. Yonezawa, K. Ishida et al.
One of the remaining issues concerning the spin-triplet superconductivity of SrRuO is the strong limit of the in-plane upper critical field H at low temperatures. In this study, we clarified the dependence of H on the angle theta between the magnetic field and the ab plane at various temperatures, b ... [Phys. Rev. B 80, 174514 (2009)] published Fri Nov 13, 2009.
Comparison of Ab initio Low-Energy Models for LaFePO, LaFeAsO, BaFe2As2, LiFeAs, FeSe and FeTe: Electron Correlation and Covalency. (arXiv:0911.3705v1 [cond-mat.supr-con])
ePrint arXiv http://arXiv.org/
Unconventional Superconductivity in the Novel Layered Superconductor Fe(Te-Se) Investigated by $^{125}$Te NMR on the Single Crystal. (arXiv:0911.3729v1 [cond-mat.supr-con])
ePrint arXiv http://arXiv.org/
Magnetic impurity resonance states and symmetry of the superconducting order parameter in iron-based superconductors. (arXiv:0911.3738v1 [cond-mat.supr-con])
ePrint arXiv http://arXiv.org/
Large transport critical currents of powder-in-tube Sr0.6K0.4Fe2As2/Ag superconducting wires and tapes. (arXiv:0911.3701v1 [cond-mat.supr-con])
ePrint arXiv http://arXiv.org/
Mesoscopics and the High $T_c$ Problem. (arXiv:0911.3695v1 [cond-mat.supr-con])
ePrint arXiv http://arXiv.org/
Influence of aging on fishtail-effect in pure and Ag-doped MG-YBCO. (arXiv:0911.3678v1 [cond-mat.supr-con])
ePrint arXiv http://arXiv.org/
Self-consistent perturbation expansion for Bose-Einstein condensates satisfying Goldstone's theorem and conservation laws. (arXiv:0911.3681v1 [cond-mat.quant-gas])
ePrint arXiv http://arXiv.org/
Spectroscopic Fingerprint of Phase-Incoherent Superconductivity in the Cuprate Pseudogap State. (arXiv:0911.3775v1 [cond-mat.supr-con])
ePrint arXiv http://arXiv.org/
Thermal Excitation of Multi-Photon Dressed States in Circuit Quantum Electrodynamics. (arXiv:0911.3797v1 [cond-mat.mes-hall])
ePrint arXiv http://arXiv.org/
In-plane electronic anisotropy in underdoped Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ revealed by detwinning in a magnetic field. (arXiv:0911.3878v1 [cond-mat.supr-con])
ePrint arXiv http://arXiv.org/
Chirality Induced Tilted-Hill Giant Nernst Signal. (arXiv:0911.2512v2 [cond-mat.str-el] UPDATED)
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