The early iron age of the Mössbauer era

The demonstration that the 14.4 keV level of⁵⁷Fe was an ideal Mössbauer example produced a veritable explosion in the discoveries of new physical phenomena. Among the important features of⁵⁷Fe are its ready availability and ease of preparation, its magnetic properties in many environments, the high intensity of its Mössbauer spectrum even at elevated temperatures, the relative sharpness of the Mössbauer lines, and the possibility of obtaining the resolution provided by this sharpness by relatively simple techniques. This paper hopes to capture some of the excitement and enthusiasm generated by the discoveries and demonstrations of the nuclear Zeeman effect, together with its polarization properties, the nuclear isomer shift, the quadrupole splitting, the temperature effect, temporal effects, nuclear hyperfine fields, transferred magnetism, the gravitational red shift, and many other new or newly elucidated phenomena.