Abstract
We herein report on the density- and temperature-dependent decay of the 93m Nb nuclear excited atom and present a simple interpretation of the underlying physics. This anomaly indicates nuclear resonant absorption and delocalisation of the long-lived Mössbauer state in the crystal. A non-linear magnetoelectric response, on low-frequency drive current, appeared in the bulk metal of a high-purity niobium crystal and then disappeared along with the disappearance of delocalised nuclear excitation. Several non-linear resonant peaks, of the order of several hundred Hertz, increased in magnitude with the applied magnetic field, and the central frequencies of these peaks decreased with temperature.