NMR Studies of Fe2P and Fe3P

A variable-frequency pulsed spectrometer was used to search for zero-field NMR lines in the two ferromagnetic compounds Fe2P and Fe3P. In Fe2P we observed spin echoes at 17.0, 20.5, 77.5, and 86.6 MHz. We deduce for the iron atoms hyperfine fields of 123 kOe (Fe II site) and 148 kOe (Fe I site). The phosphorus hyperfine fields are 45.0 kOe (P II site) and 50.2 kOe (P I site). The frequency shift under applied magnetic field indicates the phosphorus hyperfine fields are positive. The temperature dependence of the 31P NMR frequency was studied. In Fe3P a rather complicated NMR spectrum was observed. Tentatively we deduce hyperfine fields of 190, 260, and 300 kOe for the three iron sites and a phosphorus hyperfine field of 52.2 kOe. The calculated hyperfine fields for both compounds are in good agreement with previous Mössbauer data.