Yachin Ivry

Congratulations to Zuckerman Faculty Scholar Yachin Ivry, Assistant Professor at the Technion, on publishing  Asymmetry of the Ferroelectric Phase Transition in BaTiO3 in Advanced Materials.  Phase transitions are often assumed to be reversible, that is, a material should show the same key signs when it switches between two electrical states in either direction.  Dr. Ivry and his team found a crystal that can switch between two electrical states, one with built-in polarization and one without. The switch looks fundamentally different depending on direction. It shows classic first-order signs in heating, such as latent heat and two phases existing side by side, while in cooling those signatures are absent and the change looks smooth, more like a second-order transition. By combining experiments with phase field simulations, the team links this mismatch to how elastic strain energy builds up and relaxes and suggests new ways to tune these switching properties for energy related applications.

Abstract:
Symmetry changes during phase transformations fundamentally determine the behavior of thermodynamic systems, governing phenomena as diverse as water evaporation, fermion condensation, and epidemic spreading. Phase transitions are conventionally divided into two classes, and this classification is typically assumed to remain invariant upon reversing the transition…These findings reveal a first-order character upon heating but a second-order-like behavior upon cooling, challenging the conventional paradigm of symmetric phase-transition classification and suggesting new possibilities for ferroelectric-based energy storage.