Mössbauer Study of BaTh₂Fe₄As₄(N_0.7O_0.3)₂

Abstract

A superconductive BaTh2Fe4As4(N0.7O0.3)2 oxypnictide sample is synthesized using a high‐temperature solid‐state reaction route. X‐ray diffraction followed by Rietveld analysis is used for checking the phase content. 57Fe Mössbauer spectroscopy in transmission geometry is used for characterizing the hyperfine parameters of the iron site. Owing to the slightly deformed tetrahedral As coordination around Fe, the quadrupole coupling constant of Fe is nonzero, but small. This is visible in particular below 80 K. Judging by the consistency two Debye temperatures of 352 and 369 K values obtained using the total absorption and the second‐order Doppler shift, a harmonic approximation for the phonon spectra can be assumed.