Indication for macroscopic quantum tunneling below 10 K in nanostructures of SrRuO3

We study magnetization reversal of nanostructures of the itinerant ferromagnet SrRuO3 (T-c similar to 150 K). We find that down to 10 K the magnetization reversal is dominated by thermal activation. From 2-10 K, the magnetization reversal becomes independent of temperature, raising the possibility for reversal dominated by macroscopic quantum tunneling (MQT). A 10 K crossover to MQT is consistent with the extremely large anisotropy field (similar to 7 T) of SrRuO3.