Quantum ignition of deflagration in the Fe_8 molecular magnet

摘要

We report spatially resolved, time-dependent, magnetization reversal measurements of an Fe_8 single molecular magnet using a microscopic Hall bar array. We found that a deflagration process, where molecules reverse their spin direction along a moving front, can be ignited quantum mechanically (T → 0) at a resonance field, with no phonon pulse. The avalanche front velocity is of the order of 1 m/s and is sensitive to field gradients and sweep rates. We also measured the thermal diffusivity k in Fe_8. This allows us to estimate the "flame" temperature.