%0 Journal Article %A Varga, Tamas %A Droubay, Timothy C. %A Kovarik, Libor %A Nandasiri, Manjula I. %A Shutthanandan, Vaithiyalingam %A Hu, Dehong %A Kim, Bumsoo %A Jeon, Seokwoo %A Hong, Seungbum %A Li, Yulan %A Chambers, Scott A. %D 2017 %T Coupled Lattice Polarization and Ferromagnetism in Multiferroic NiTiO3 Thin Films %U https://acs.figshare.com/articles/journal_contribution/Coupled_Lattice_Polarization_and_Ferromagnetism_in_Multiferroic_NiTiO_sub_3_sub_Thin_Films/5142148 %R 10.1021/acsami.7b04481.s001 %2 https://acs.figshare.com/ndownloader/files/8749006 %K MTiO 3 transition metal titanates %K NiTiO 3 %K oxide epitaxy %K phase-field approach %K multiferroic family %K crystal growth %K WFM %K ferromagnetism %K metastable materials %K four-stage memories %K LiNbO 3 %K epitaxial strain %K work validates symmetry-based criteria %K ferroic order parameters %K type compounds %K thin-film NiTiO 3 %K coexistence %K Multiferroic NiTiO 3 %K LiNbO 3 substrate %K electromagnetic switches %K LiNbO 3 structure %K first-principles calculations %K MTiO 3 %K polarization %K order parameters %K Films Polarization-induced %K Lattice Polarization %K bulk FeTiO 3 %X 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. %I ACS Publications