Robust multiferroicity and magnetic modulation of the ferroelectric imprint field in heterostructures comprising epitaxial Hf_0.5Zr_0.5O₂ and Co

resumo

Magnetoelectric multiferroics, either single-phase or composites comprising ferroelectric/ferromagnetic coupled films, are promising candidates for energy efficient memory computing. However, most of the multiferroic magnetoelectric systems studied so far are based on materials that are not compatible with industrial processes. Doped hafnia is emerging as one of the few CMOS-compatible ferroelectric materials. Thus, it is highly relevant to study the integration of ferroelectric hafnia into multiferroic systems. In particular, ferroelectricity in hafnia, and the eventual magnetoelectric coupling when ferromagnetic layers are grown atop of it, are very much dependent on quality of interfaces. Since magnetic metals frequently exhibit noticeable reactivity when grown onto oxides, it is expected that ferroelectricity and magnetoelectricity might be reduced in multiferroic hafnia-based structures. In this article, we present excellent ferroelectric endurance and retention in epitaxial Hf0.5Zr0.5O2 films grown on buffered silicon using Co as the top electrode. The crucial influence of a thin Pt capping layer grown on top of Co on the ferroelectric functional characteristics is revealed by contrasting the utilization of Pt-capped Co, non-capped Co and Pt. Magnetic control of the imprint electric field (up to 40% modulation) is achieved in Pt-capped Co/Hf0.5Zr0.5O2 structures, although this does not lead to appreciable tuning of the ferroelectric polarization, as a result of its high stability. Computation of piezoelectric and flexoelectric strain-mediated mechanisms of the observed magnetoelectric coupling reveal that flexoelectric contributions are likely to be at the origin of the large imprint electric field variation.

palavras-chave

TOTAL-ENERGY CALCULATIONS

categoria

Chemistry; Materials Science

autores

Zakusylo, T; Quintana, A; Lenzi, V; Silva, JPB; Marques, L; Yano, JLO; Lyu, J; Sort, J; Sánchez, F; Fina, I

Grupos

G6 - Materiais Virtuais e Inteligência Artificial

Projectos

Collaboratory for Emerging Technologies, CoLab (EMERGING TECHNOLOGIES)

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

agradecimentos

Financial support from the Spanish Ministry of Science, Innovation and Universities and European Union NextGenerationEU/PRTR (MCIN/AEI/10.13039/501100011033), through the Severo Ochoa FUNFUTURE (CEX2019-000917-S), PID2023-147211OB-C21, PDC2023-145874-I00, PID2020-116844RB-C21, PID2020-112548RB-I00, and PID2019-107727RB-I00 projects program, from Generalitat de Catalunya (2021 SGR 00804 and 2021 SGR 00651) and the European Research Council (2021-ERC-Advanced 'REMINDS' Grant No. 101054687) is acknowledged. We also acknowledge projects TED2021-130453B-C21 and TED2021-130453B-C22, funded by MCIN/AEI/10.13039/50110001103. This work was supported by: (i) the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding Contract UIDB/04650/2020; (ii) the exploratory research project 2022.01740.PDTC (https://doi.org/10.54499/2022.01740.PTDC) and (iii) the project M-ERA-NET3/0003/2021 - NanOx4EStor grant agreement No 958174 (https://doi.org/10.54499/M-ERA-NET3/0003/2021). J. P. B. S. also thanks FCT for the contract under the Institutional Call to Scientific Employment Stimulus - 2021 Call (CEECINST/00018/2021). This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MCTES (PIDDAC). Guillaume Sauthier from ICN2 is aknowledged for assistance on the XPS characterization. Francisco Javier Campos Lopez is aknowledged for assistance on the X-ray characterization.