Noise and finite size effects in multiferroics with strong elastic interactions

The size dependence of yield point assisted ferroelastic switching is dominated by the appearance of a minimum size where the domain switching by external strain is swamped by noise which is determined by internal jamming processes. The lower ferroelastic lateral cut-off size was found in computer simulations to be 200 × 202 unit cells for hard materials and 40 × 42 unit cells for soft materials. The corresponding length scales are 16 nm and 4 nm, respectively. These lengths are greater than the minimum length to sustain a twinned sample (∼1 nm). Elastic interactions modify the switching behavior of multiferroics at larger lengths but do not prevent elastic switching above these noise cut-offs.