Magnetic and Mössbauer spectral studies of R3Fe29−xMox compounds (R = Y, Nd, Sm, Gd, Tb, and Dy)

The investigation of the structure, magnetic and Mössbauer properties for the series of R3(Fe,Mo)29 compounds has been performed, where R = Y, Nd, Sm, Gd, Tb, and Dy. The crystallographic structure of the ternary phase compounds has been investigated by Rietveld refinement of the X-ray diffraction patterns obtained at room temperature. The quality of the single-phase compounds was also checked by thermomagnetic measurements, from room temperature to above the Curie temperatures. From the magnetic isotherms for the free powder samples, measured at 4.2 K, the saturation magnetizations and the iron average magnetic moments have been derived. 57Fe Mössbauer spectra of the R3(Fe,Mo)29 compounds have been measured at 15 K. The analysis of spectra, in a model which takes into account both the Fe atom nearest neighbor numbers and the FeFe nearest neighbor bond lengths, indicates that the transferred contribution to the hyperfine field at the iron sites, due to rare earth moments, can be correlated with the rare earth effective spin.