Engineering of Crystal and Domain Structures in Epitaxial Y:HfO ₂ Thin Films by YSZ Substrate Miscut

films with atomically smooth surfaces were fabricated by magnetron sputtering on both nominally-flat and 8°-miscut (001) YSZ single-crystal substrates. On nominally-flat substrates, (100)-oriented orthorhombic films form a two-variant domain structure and evolve into (001)-oriented monoclinic phases at larger thicknesses. On 8°-miscut substrates, in contrast, a (100)-oriented orthorhombic phase with a preferential population among the two variants is stabilized at small thicknesses, whereas a reoriented, (100)-oriented monoclinic phase is favored at larger thicknesses, accompanied by a pronounced narrowing of the orthorhombic stability window. This work provides fundamental insight into the control of phase stability and domain architecture in polymorphic oxides, relevant to the integration of complex oxides in advanced electronic platforms.