Epitaxy-driven ferroelectric/non-ferroelectric polymorph selection in an all-fluorite system

Barriuso, Eduardo ; Jiménez, Ricardo ; Langenberg, Eric ; Koutsogiannis, Panagiotis ; Larrea, Ángel ; Varela, Manuel ; Magén, César ; Algarabel, Pedro A. ; Algueró, Miguel ; Pardo, José A. (Universidad de Zaragoza)

Resumen: Films of ferroelectric hafnia have hitherto been deposited on electrodes with a non‐fluorite crystal structure. As a result, they are polycrystalline, contain fractions of non‐ferroelectric polymorphs or have poor crystal quality. Here, a strategy that circumvents all these limitations is shown. Seven nanometers‐thick epitaxial Hf0.5Zr0.5O2 (HZO) films are deposited directly on yttria‐stabilized zirconia (YSZ) single‐crystals. The fluorite structure of the whole system enables coherent epitaxy, while the substrate orientation induces polymorph‐selective growth, being the HZO films orthorhombic on YSZ(111) and monoclinic on YSZ(001). Besides, the YSZ substrate can play the role of a buried floating electrode under the appropriate measuring conditions (temperature and frequency) thanks to its thermally‐activated oxygen conductivity. Indeed, out‐of‐plane ferroelectric switching is confirmed in the orthorhombic HZO samples at 185 °C and 0.01 Hz frequency. This original approach avoids the need to deposit conducting bottom layers, allowing high‐quality orthorhombic hafnia to be obtained directly on the substrate and its ferroelectric nature to be studied. Moreover, it constitutes a case of ion‐driven ferroelectric switching, and thus gives support to the recently proposed relationship between ionic conductivity, and ferroelectricity in fluorite systems.

Idioma: Inglés

DOI: 10.1002/aelm.202300522

Año: 2024

Publicado en: Advanced Electronic Materials 10, 5 (2024), 2300522 [8 pp.]
ISSN: 2199-160X

Factor impacto JCR: 5.3 (2024)

Categ. JCR: PHYSICS, APPLIED rank: 43 / 187 = 0.23 (2024) - Q1 - T1
Categ. JCR: NANOSCIENCE & NANOTECHNOLOGY rank: 52 / 147 = 0.354 (2024) - Q2 - T2
Categ. JCR: MATERIALS SCIENCE, MULTIDISCIPLINARY rank: 140 / 460 = 0.304 (2024) - Q2 - T1

Factor impacto SCIMAGO: 1.478 - Electronic, Optical and Magnetic Materials (Q1)

Financiación: info:eu-repo/grantAgreement/ES/AEI/PID2019-107338RB-C64
Financiación: info:eu-repo/grantAgreement/ES/MICINN-AEI/PID2020-112914RB-100/AEI/10.13039/501100011033
Financiación: info:eu-repo/grantAgreement/ES/MICINN/AEI/PID2021-128281NA-I00
Financiación: info:eu-repo/grantAgreement/ES/MICINN/AEI/TED2021-130871B-C21

Tipo y forma: Article (Published version)

Área (Departamento): Área Cienc.Mater. Ingen.Metal. (Dpto. Ciencia Tecnol.Mater.Fl.)