Reversible metal-hydride phase transformation in epitaxial films.

Metal-hydride phase transformations in solids commonly proceed with hysteresis. The extrinsic component of hysteresis is the result of the dissipation of energy of internal stress due to plastic deformation and fracture. It can be mitigated on the nanoscale, where plastic deformation and fracture are suppressed and the transformation proceeds through formation and evolution of coherent phases.

Formation of self-assembled nanoplates via hydrogenation of epitaxial Pd film.

Understanding the relationship between the uptake of hydrogen gas and hydride phase formation and evolution in metal solids is a phenomenon of significant technological importance due to current development of hydrogen storage devices, sensors, and membranes. The performance of these devices is degraded by structural defect formation during incoherent metal-hydride phase transformation. In this work, atomic force and scanning electron microscopy reveal formation of nanoplates along the ⟨111⟩ directions in a (111) epitaxial Pd film.