A 57Fe Moessbauer Spectroscopy Study of the 7 K Superconductor LaFePO

Marcus Tegel; Inga Schellenberg; Rainer Pöttgen; Dirk Johrendt

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arXiv · 0805.1208

A 57Fe Moessbauer Spectroscopy Study of the 7 K Superconductor LaFePO

Marcus Tegel·Inga Schellenberg·Rainer Pöttgen·Dirk Johrendt

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Abstract

A polycrystalline sample of superconducting LaFePO was prepared in a tin flux at 1123 K. The structure was determined from single crystal data (ZrCuSiAs-type, P4/nmm, a = 3.9610(1), c = 8.5158(2) A, Z = 2) and the phase analysis was performed by the Rietveld method. LaFePO is Pauli-paramagnetic and becomes superconducting at 7 K after removing the ferromagnetic impurity phase Fe2P from the sample. 57Fe Moessbauer spectroscopy measurements at 298, 77, 4.2 and 4 K show single signals at isomer shifts around 0.35 mm/s, subject to weak quadrupole splitting. At 4 K, a symmetric line broadening appears, resulting from a small transferred magnetic hyperfine field of 1.15(1) T and accompanied by an angle of 54.7(5) between Bhf and Vzz, the main component of the electric field gradient tensor.

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Marcus Tegel, Inga Schellenberg, Rainer Pöttgen, Dirk Johrendt. 2008-05-08. A 57Fe Moessbauer Spectroscopy Study of the 7 K Superconductor LaFePO. https://arxiv.org/abs/0805.1208

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