Lattice Effects Across the Phase Diagram of Pnictides

Liarokapis, E.; Antonakos, A.; Zhigadlo, N. D.; Katrych, S.; Karpiński, J.

doi:10.1007/s10948-012-1973-7

Cited by 1 publication

(1 citation statement)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Finally, the even larger value of the Fe phonon should be due to an increased anharmonicity of this mode compared to Sm and As, as the low temperature Raman measurements also indicate (stronger softening of this mode with temperature, Ref. [23]). The considerable difference between the Grüneisen parameters must be related with the observed anisotropic compression of the FeAs 4 tetrahedra [17].…”

Section: Data Analysis and Discussionmentioning

confidence: 88%

Non-linear lattice response of Sm oxypnictides to hydrostatic pressure

Liarokapis

Calamiotou

Zhigadlo

et al. 2013

Journal of Physics and Chemistry of Solids

Self Cite

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

Section: Data Analysis and Discussionmentioning

confidence: 88%