Observation of lattice softening at $T_{\mathrm{c}}$ in the FeSe${}_{0.5}$Te${}_{0.5}$ superconductor

Abstract

Polycrystalline samples of FeSe${}_{0.5}$Te${}_{0.5}$ were synthesized using a conventional solid-state reaction method. The onset of bulk superconductivity transition was confirmed by SQUID magnetometry at 12.5~K. ${}^{57}$Fe Mössbauer spectra in transmission geometry were recorded at temperatures between 6.0 and 320 K. Both the isomer shift and the total absorption started to drop about $T_c$, indicating a softening of the lattice. The drop is estimated to correspond to at least 60~K from the original Debye temperature ${\theta }_{\mathrm{D}}\approx 460$~K. Seebeck measurements indicate that the samples are $n$-type conductors at low temperatures with a cross-over to $p$-type conductivity around 135 K. The zero Seebeck coefficient is seen below $10.6$~K.

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References in corpus (11)

• Effect of Structural Parameters on Superconductivity in Fluorine-Free LnFeAsO1-y (Ln=La,Nd)
• The crystal structure of FeSe0.44Te0.56
• Pressure-induced high-Tc superconducting phase in FeSe: correlation between anion height and Tc
• Frustrated Magnetic Interactions, Giant Magneto-Elastic Coupling, and Magnetic Phonons in Iron-Pnictides
• Spin Ordering in LaOFeAs and Its Suppression in Superconductor LaO0.89F0.11FeAs Probed by Mössbauer Spectroscopy
• Seebeck effect in Fe1+xTe1-ySey single crystals
• Effect of magnetic field on the spin resonance in FeTe(0.5)Se(0.5) as seen via inelastic neutron scattering
• Moessbauer spectroscopy evidence for the lack of iron magnetic moment in superconducting FeSe
• Antiferromagnetic fluctuations in Fe(Se1-xTex)0.92 (x = 0.75, 1) observed by inelastic neutron scattering
• Phonon spectra in CaFe2As2 and Ca0.6Na0.4Fe2As2: Measurement of the pressure and temperature dependence and comparison with ab-initio and shell model calculations
• Effect of K Doping on Phonons in Ba1-xKxFe2As2

Cited by in corpus (7)

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• Electric field gradient wave (EFGW) in iron-based superconductor Ba(0.6)K(0.4)Fe2As2 studied by Mössbauer spectroscopy
• 57Fe Mossbauer study of Lu2Fe3Si5 iron silicide superconductor
• Phonon Spectra in the Parent Superconducting Iron-tuned Telluride Fe${}_{1+x}$Te from Inelastic Neutron Scattering and Ab Initio Calculations