Coupled Lattice Polarization and Ferromagnetism in Multiferroic NiTiO ₃ Thin Films

Journal Article · Thu Jun 22 04:00:00 EDT 2017 · ACS Applied Materials and Interfaces

DOI:https://doi.org/10.1021/acsami.7b04481· OSTI ID:1373099

Varga, Tamas; Droubay, Timothy C.; Kovarik, Libor; Nandasiri, Manjula I. ^[1]; Shutthanandan, Vaithiyalingam; Hu, Dehong; Kim, Bumsoo ^[2]; Jeon, Seokwoo ^[3]; Hong, Seungbum ^[2]; Li, Yulan; Chambers, Scott A.

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1. Imaging and Chemical Analysis Laboratory, Montana State University, Bozeman, Montana 59717, United States
2. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States; Department of Materials Science and Engineering, KAIST, Daejeon 34141, Republic of Korea
3. Department of Materials Science and Engineering, KAIST, Daejeon 34141, Republic of Korea

Polarization-induced weak ferromagnetism (WFM) was demonstrated a few years back in LiNbO3-type compounds, MTiO3 (M = Fe, Mn, Ni). Although the coexistence of ferroelectric polarization and ferromagnetism has been demonstrated in this rare multiferroic family before, first in bulk FeTiO3, then in thin-film NiTiO3, the coupling of the two order parameters has not been confirmed Here, we report the stabilization of polar, ferromagnetic NiTiO3 by oxide epitaxy on a LiNbO3 substrate utilizing tensile strain and demonstrate the theoretically predicted coupling between its polarization and ferromagnetism by X-ray magnetic circular dichroism under applied fields. The experimentally observed direction of ferroic ordering in the film is supported by simulations using the phase-field approach. Our work validates symmetry-based criteria and first-principles calculations of the coexistence of ferroelectricity and WFM in MTiO3 transition metal titanates crystallizing in the LiNbO3 structure. It also demonstrates the applicability of epitaxial strain as a viable alternative to high-pressure crystal growth to stabilize metastable materials and a valuable tuning parameter to simultaneously control two ferroic order parameters to create a multiferroic. Multiferroic NiTiO3 has potential applications in spintronics where ferroic switching is used, such as new four-stage memories and electromagnetic switches.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division; USDOE Office of Science - Office of Biological and Environmental Research
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1373099
• Journal Information: ACS Applied Materials and Interfaces, Journal Name: ACS Applied Materials and Interfaces Journal Issue: 26 Vol. 9; ISSN 1944-8244
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
epitaxial film
epitaxial strain
ferroic properties
multiferroic
nickel titanate