Magnetic avalanches of minor fast-relaxing species of Mn12 acetate

Using micron-sized thermometers and Hall bars, we report time resolved studies of the local temperature and local magnetization for two types of magnetic avalanches (abrupt spin reversals) in the molecular magnet Mn-12 acetate, corresponding to avalanches of the main slow-relaxing crystalline form and avalanches of the fast-relaxing minor species that exists in all as-grown crystals of this material. An experimental protocol is used that allows the study of each type of avalanche without triggering avalanches in the other, and of both types of avalanches simultaneously. In samples prepared magnetically to enable both types of avalanches, minor species avalanches are found to act as a catalyst for the major species avalanches.