DOI: 10.1063/1.5041715

This study is the first on ferroelectric hafnium oxide published by the MULFOX group. This ferroelectric metastable phase is quite a new topic, and in this work they present its excellent ferroelectric properties, including fatigue and retention. 

Abstract: Ferroelectric orthorhombic Hf_0.5Zr_0.5O₂ thin films have been stabilized epitaxially on La_2/3Sr_1/3MnO₃/SrTiO₃(001) by pulsed laser deposition. The epitaxial orthorhombic films, (111)-oriented and with a very flat surface, show robust ferroelectric properties at room temperature. They present a remnant polarization around 20 μC/cm² without the need of a wake-up process, a large coercive electric field of around 3 MV/cm, an extremely long retention extending well beyond 10 years, and an endurance up to about 10⁸ cycles.

Such outstanding properties in the nascent research on epitaxial HfO₂-based ferroelectric films can pave the way for a better understanding of the effects of orientation, interfaces, strain, and defects on ferroelectricity in HfO₂.