A Fitting Procedure for Magnetic Multiphase Materials Moessbauer Spectra

In this work a practical method of fitting complex multiphase Moessbauer effect spectra is proposed. The task is simplified imposing specific restrictions to the analysing functions, which are appropriate for cases where the component phases spectra do not change substantially during the process under study. The ME spectra can be analysed using the phases subspectra, by defining only a reduced number of parameters. The constraints are equivalent to assume a Doppler velocity transformation v'=(v-δm)Bm0/Bm+δm0 for each phase, where δm and Bm are fitting parameters containing information on the phase mean isomer shift and hyperfine field and δm0 and Bm0 their reference values. In this manner physically meaningful results are easy to obtain. The idea was applied to partially nitrogenated R2Fe17Nx (R= Sm and Y) and partially hydrogen-decomposed Nd-Fe-B materials