Magnetic and thermal Mössbauer effect scans: a new approach

Mossbauer transmission recorded at fixed photon energies as a function of a given physical parameter such as temperature, external field, etc. (Mossbauer scan), is being developed as a useful quantitative tool, complementary of Mossbauer spectroscopy. Scans are performed at selected energies, suitable for the observation of a given physical property or process. It is shown that one of main advantages of this approach is the higher speed at which the external physical parameter can be swept, which allows the recording of quasicontinuous experimental response functions as well as the study of processes which occur too fast to be followed by Mossbauer spectroscopy. The applications presented here are the determination of the temperature dependence of the 57Fe hyperfine field in FeSn2, the thermal evolution and nanocrystallization kinetics of amorphous Fe73.5Si13.5Cu1Nb3B9 and complex behaviour could be related to polarization effects which appear in thick absorbers [10]. To confmn this behaviour, a few spectra were recorded under external fields (H j =−70.6, −15.3 and 0 Oe). In Figure 5b,c, the full circles are the values Tr(E 5,H j ) and Tr(E6,Hj), respectively obtained from the spectra, and they agree with the behaviour revealed by the scan. The analysis of the physics beneath these results is left for a forthcoming article, but we found worthily to remark that its observation was possible by performing only one scan at energy E 5.