Compatibility, Hysteresis and the Direct Conversion of Heat to Electricity
Big first order phase transformations in solids can still be highly reversible, if the lattice parameters are “tuned” to satisfy certain relations that promote the compatibility between phases. We present recent measurements of hysteresis in martensitic materials resulting from this kind of tuning. We re-examine the origins of hysteresis in light of these measurements, and conclude that a certain energy barrier, not pinning or thermal activation, is primarily responsible for hysteresis in a broad array of materials that undergo phase transformations.