Origin of the anomalous acoustic paramagnetic resonance absorption observed in saturated spin systems

Abstract
Anomalous and unexplained variations of the acoustic paramagnetic resonance absorption, observed in saturated spin systems by a conventional pulse-echo technique, have been encountered by several groups of workers. It is suggested that the phenomenon can be explained on the basis of a nonuniform distribution of paramagnetic ions in the sample. Some experiments are described that support this hypothesis.