Improved polarization and endurance in ferroelectric Hf0.5Zr0.5O2 films on SrTiO3(110)

The metastable orthorhombic phase of Hf0.5Zr0.5O2 (HZO) can be stabilized in thin films on La0.67Sr0.33MnO3 (LSMO) buffered (001)-oriented SrTiO3 (STO) by an intriguing epitaxy that results in (111)-HZO oriented growth and robust ferroelectric properties. Here, we shown that the orthorhombic phase can also be epitaxially stabilized on LSMO/STO(110), presenting the same out-of-plane (111) orientation but a different distribution of in-plane crystalline domains. The remanent polarization of HZO films with a thickness of less than 7 nm on LSMO/STO(110) is 33 µC cm-2, which corresponds to a 50% improvement over equivalent films on LSMO/STO(001). Furthermore, HZO on LSMO/STO(110) presents higher endurance, switchable polarization is still observed up to 4x1010 cycles, and retention of more than 10 years. These results demonstrate that tuning epitaxial growth of ferroelectric HfO2, here by using STO(110) substrates, allows improving functional properties of relevance for memory applications.Financial support from the Spanish Ministry of Science and Innovation, through the Severo Ochoa FUNFUTURE (CEX2019- 000917-SMCIN, AEI/10.13039/501100011033), PID2020- 112548RB-I00 (MCIN/AEI/10.13039/501100011033) and PID2019-107727RB-I00 (MCIN/AEI/10.13039/501100011033) projects, from CSIC through the i-LINK (LINKA20338) program, and from Generalitat de Catalunya (2017 SGR 1377) is acknowledged. Project supported by a 2020 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation. IF acknowledges Ramón y Cajal contract RYC-2017-22531. TS and HT are financially supported by China Scholarship Council (CSC) with No. 201807000104, and 201906050014. TS and HT work has been done as a part of their Ph.D. program in Materials Science at Universitat Autònoma de Barcelona.Peer reviewe