title: Interface strain-induced multiferroicity in a SmFeO3 film.
abstract: An epitaxial pseudocubic SmFeO3 thin film on (100) Nb-SrTiO3 was studied based on ferroelectric (FE) characterization and magnetic measurements. High-resolution transmission electron microscopy images clarify the nature of the epitaxial growth, the stress-induced structural distortion at the film/substrate interface, and the existence of two different orientation lattices. Clear grain boundaries can be seen, which could introduce an extra local distortion. Rectangular FE loops can be observed at room temperature, even by just applying a small voltage ranging from -1 to +1 V, indicative of the presence of FE polarization. Piezoelectric force microscopy images confirm the existence of FE domains and the switchable polarization. A strong ferromagnetic-like transition occurs around 185 K, which is much lower than the transition observed in the bulk sample. It is believed that the pseudocubic structure enhances FE polarization and decreases the magnetic ordering temperature, which is confirmed by the first-principles theoretical calculations. Meanwhile, the ferroelectricity in this thin film should originate from distortion and modification in the structural modules rather than from the exchange striction interaction that is found in the bulk SmFeO3.
authors.affiliation: Institute for Superconducting and Electronics Materials, University of Wollongong, Innovation Campus , North Wollongong, New South Wales 2519, Australia.
authors.forename: Zhenxiang
authors.initials: Z
authors.lastname: Cheng
authors.forename: Fang
authors.initials: F
authors.lastname: Hong
authors.forename: Yuanxu
authors.initials: Y
authors.lastname: Wang
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Ozawa
authors.forename: Hiroki
authors.initials: H
authors.lastname: Fujii
authors.forename: Hideo
authors.initials: H
authors.lastname: Kimura
authors.forename: Yi
authors.initials: Y
authors.lastname: Du
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Wang
authors.forename: Shixue
authors.initials: S
authors.lastname: Dou