Single crystals of superconducting SmFeAsO1−xFygrown at high pressure

Zhigadlo, N. D.; Katrych, S.; Bukowski, Z.; Weyeneth, S.; Puźniak, R.; Karpiński, J.

doi:10.1088/0953-8984/20/34/342202

Cited by 141 publications

(151 citation statements)

References 10 publications

Supporting

Mentioning

141

Contrasting

Order By: Relevance

“…SmFeAsO 0.8 F 0.15 single crystals with an approximate size of 100 Â 100 Â 6 mm 3 (shown in Fig. 1c) and submicrogram mass were grown at ETH Zurich in a highpressure synthesis procedure using NaCl/KCl flux 18,19 . Two SmFeAsO 0.8 F 0.15 crystals were irradiated at the ATLAS facility at Argonne National Laboratory with 1.4-GeV Pb -ions to doses of N ¼ 2 Â 10 11 (sample no.…”

Section: Resultsmentioning

confidence: 99%

Huge critical current density and tailored superconducting anisotropy in SmFeAsO0.8F0.15 by low-density columnar-defect incorporation

et al. 2013

View full text Add to dashboard Cite

Iron-based superconductors could be useful for electricity distribution and superconducting magnet applications because of their relatively high critical current densities and upper critical fields. SmFeAsO 0.8 F 0.15 is of particular interest as it has the highest transition temperature among these materials. Here we show that by introducing a low density of correlated nano-scale defects into this material by heavy-ion irradiation, we can increase its critical current density to up to 2 Â 10 7 A cm À 2 at 5 K-the highest ever reported for an ironbased superconductor-without reducing its critical temperature of 50 K. We also observe a notable reduction in the thermodynamic superconducting anisotropy, from 8 to 4 upon irradiation. We develop a model based on anisotropic electron scattering that predicts that the superconducting anisotropy can be tailored via correlated defects in semimetallic, fully gapped type II superconductors.

show abstract

Section: Resultsmentioning

confidence: 99%

Huge critical current density and tailored superconducting anisotropy in SmFeAsO0.8F0.15 by low-density columnar-defect incorporation

et al. 2013

View full text Add to dashboard Cite

show abstract

“…The preparation of the samples is described elsewhere [14][15][16]. Typical size of the single crystals was a few hundred micrometers while for the polycrystals of the order of a few microns.…”

Section: Methodsmentioning

confidence: 99%

Non-linear lattice response of Sm oxypnictides to hydrostatic pressure

Liarokapis

Calamiotou

Zhigadlo

et al. 2013

Journal of Physics and Chemistry of Solids

View full text Add to dashboard Cite

Hydrostatic pressure Raman measurements have been carried out on the SmFeAsO series of oxypnictides with varying amount of doping (F substitution for O and Co for Fe) and transition temperature (T c ), in order to investigate lattice modifications and their connection to doping and superconductivity. Synchrotron XRD data on some of these compounds indicated that at low doping the lattice constants vary smoothly with pressure, but with increasing F concentration there is a deviation from the normal equation of state and these effects are related with modifications in the superconducting FeAs 4 tetrahedra. The hydrostatic pressure Raman measurements show that the A 1g mode of the rare earth atom for the superconducting compounds deviates from the linear pressure dependence at the same pressures where the XRD results indicate pressure-induced lattice anomalies. A similar anomaly is found for the As phonon of same symmetry. As in cuprates, the effect is diminished in the undoped compounds and it is not related with the F substitution being present in the Sm(Fe 1-x Co x )AsO as well. The calculated Grüneisen parameter for the Sm phonon (γ≈1.5) is very similar to the corresponding values of cuprates and it does not vary with doping. For the Fe mode it has higher value (γ≈1.8) than for As (γ≈1) indicating a more anharmonic phonon.

show abstract

“…14,15 Our magnetization measurements on SmFeAsO using a superconducting quantum interference device show magnetic ordering at T N = 130 K, and the superconducting transition in the nominally doped SmFeAsO 0.60 F 0.35 takes place at T c = 53 K. Contrary to 122 pnictide single crystals, the samples available are of very small size ͑about 100ϫ 100ϫ 20 m 3 for the ones we used in this experiment͒ and consequently their phonon dispersions can only be investigated using IXS. The IXS experiments were carried out on beamline ID28 at the European Synchrotron Radiation Facility, with a photon energy of 21.747 keV and an energy resolution of 2.0 meV.…”

mentioning

confidence: 98%

Inelastic x-ray scattering study of superconductingSmFeAsO1−xFysingle crystals: Evidence for strong momentum-dependent doping-induced renormalizations of optical phonons

et al. 2009

View full text Add to dashboard Cite

We report inelastic x-ray scattering experiments on the lattice dynamics in SmFeAsO and superconducting SmFeAsO 0.60 F 0.35 single crystals. Particular attention was paid to the dispersions along the ͓100͔ direction of three optical modes close to 23 meV, polarized out of the FeAs planes. Remarkably, two of these modes are strongly renormalized upon fluorine doping. These results provide significant insight into the energy and momentum dependence of the coupling of the lattice to the electron system and underline the importance of spin-phonon coupling in the superconducting iron pnictides. DOI: 10.1103/PhysRevB.80.220504 PACS number͑s͒: 74.25.Kc, 63.20.Ϫe, 74.25.Gz, 78.70.Ck The recent discovery of superconductivity in FeAs-based compounds has stimulated considerable interest. 1 To date three distinct families of FeAs-based superconductors with respective formulas XFeAs ͑X =Li or Na͒, MFe 2 As 2 ͑M =Ca,Ba,Sr͒, and REFeAsO ͑where RE is a rare-earth metal͒-the so-called "111's," "122's," and "1111's"-have been identified. Among them, the last family has the highest values of the superconducting transition temperature T c : depending on the lanthanide, T c can be as high as 55 K. 2 The high value of T c and early DFT calculations 3 initially appeared to support the notion of an exotic mechanism for superconductivity in these materials. However, recent experiments have established that the role of phonons in the electron coupling cannot be totally ignored. In particular, the observation of large Fe isotope effects 4 and the fact that the Fe-As configuration is intimately related to T c ͑Ref. 5͒ and to the magnetic state of the iron sublattice 6,7 show that the lattice is actively involved in this problem. In addition, substantial deviations have been found between the experimentally observed phonon density of states ͑PDOS͒ and ab initio calculations, 8 suggesting that these calculations do not capture all the relevant physics. A spin-polarized calculation is, for example, required to obtain good agreement with the experimental phonon dispersion in the case of undoped CaFe 2 As 2 , even above the magnetic ordering temperature T N . 9 Furthermore, it was recently demonstrated that zonecenter Raman active phonons are strongly renormalized at T N in Ba 1−x K x Fe 2 As 2 ͑Ref. 10͒ and Ba͑Fe 1−x Co x ͒ 2 As 2 . 11 These results all highlight the role of spin-phonon coupling in iron pnictides.In previous experiments on NdFeAsO 1−x F x powders, an unexpected signature of the doping in the PDOS was discovered. 12 In particular, it was found that even at room temperature, at least one of the three phonon branches located around 23 meV softens on doping. All the three modes are polarized out of the ͑Fe,As͒ planes, parallel to the c axis, and involve motions of either the As or Fe ions. At least one of the modes couples directly to the magnetic iron sublattice. 7,13 Here, we utilize inelastic x-ray scattering ͑IXS͒ to investigate the phonon dispersions of SmFeAsO and superconducting SmFeAsO 0.60 F 0.35 single crystals, with...

show abstract

Single crystals of superconducting SmFeAsO_1−xF_ygrown at high pressure

Cited by 141 publications

References 10 publications

Huge critical current density and tailored superconducting anisotropy in SmFeAsO0.8F0.15 by low-density columnar-defect incorporation

Huge critical current density and tailored superconducting anisotropy in SmFeAsO0.8F0.15 by low-density columnar-defect incorporation

Non-linear lattice response of Sm oxypnictides to hydrostatic pressure

Inelastic x-ray scattering study of superconductingSmFeAsO1−xFysingle crystals: Evidence for strong momentum-dependent doping-induced renormalizations of optical phonons

Contact Info

Product

Resources

About