Paramagnetic Phase of a Heavy-Fermion Compound, CeFePO, Probed by 57Fe M\"{o}ssbauer Spectroscopy

TL;DR

This study uses 57Fe Mössbauer spectroscopy to investigate the magnetic properties of CeFePO, revealing a paramagnetic phase with no magnetic splitting across a broad temperature range and providing insights into its electronic state.

Contribution

It is the first detailed Mössbauer spectroscopic analysis of CeFePO, demonstrating its paramagnetic behavior and comparing its electronic state to related iron-based compounds.

Findings

CeFePO remains paramagnetic from 9.4 to 293 K.

The Debye temperature of CeFePO is approximately 448 K.

The Fe valence state in CeFePO is similar to other layered iron-based oxypnictides.

Abstract

57Fe M\"{o}ssbauer spectroscopy was applied to an iron-based layered compound CeFePO. At temperatures from 9.4 to 293 K, no magnetic splitting was observed in the M\"ossbauer spectra of CeFePO indicating a paramagnetic phase of the Fe magnetic sublattice. All the spectra were fitted with a small quadrupole splitting, and the Debye temperature of CeFePO was found to be \sim448 K. The isomer shift at room temperature, 0.32 mm/s, was almost equal to those of LnFeAsO (Ln = La, Ce, Sm). Comparing s-electron density using the isomer shifts and unit cell volumes, it was found that the Fe of CeFePO has a similar valence state to other layered iron-based quaternary oxypnictides except LaFePO.