Magnetic fatigue : Effect of seismic-related loading on magnetic and structural behavior of magnetite

Powders of multidomain magnetite were subjected to fatigue-related cyclic loading at ambient conditions between 30 and 500°C using a dynamical mechanical analysis system. The mechanical losses, tan δ, are sensitive to the loading frequency and correlate with decreasing coherent crystallite size of the magnetite and its lattice distortion. While the selected loading frequencies are similar to those observed during earthquake propagation, the observed signatures of magnetic fatigue are discussed towards understanding the physics of natural and human-induced seismic events.