Collective magnetic dynamics in artificial spin ice probed by ac susceptibility

We report on the study of the thermal dynamics of square artificial spin ice, probed by means of temperature and frequency dependent AC susceptibility. Pronounced influence of the inter-island coupling strength was found on the frequency response of the samples. Subsequent analysis of the frequency and coupling dependent freezing temperatures in the framework of the Vogel-Fulcher-Tammann law, discusses the interpretation of these phenomenological parameters in terms of the sample microscopic features. The high sensitivity and robust signal to noise ratio of AC susceptibility, validates the latter as a promising and simple experimental technique for resolving the dynamics and temperature driven dynamics crossovers for the case of artificial spin ice.