Athermal Transformation Behavior and Thermal Hysteresis at the Sio2-Alpha/Beta-Cristobalite Phase-Transition
European Journal of Mineralogy 5(2): 377-380
The alpha/beta-phase-transition of cristobalite (SiO2) shows a stable and reproducible hysteresis loop with phase coexistence on both slopes. The transition proceeds as a function of temperature rather than isothermally. The non-thermally-activated (athermal) behaviour is analogous to martensitic transformations in metals and alloys, and similar to the hysteresis of ferroics in an applied field. The observations suggest that self-pinning by coherency-strain is the cause of the 'thermal' hysteresis of non-quenchable structural phase transitions.