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

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