Phase stability and B-site ordering in La2NiMnO6 thin films

Abstract

Thin films of multiferroic double-perovskite La2NiMnO6 are prepared on (001)-oriented SrTiO3, (La0.289Sr0.712)(Al0.633Ta0.356)O3, and LaSrAlO4 substrates by pulsed laser deposition. Microstructure investigation by advanced electron microscopy shows that the La2NiMnO6 films have a monoclinic structure on the SrTiO3 substrates and a rhombohedral structure on the (La0.289Sr0.712)(Al0.633Ta0.356)O3 and LaSrAlO4 substrates. Atomic-scale elemental maps of the monoclinic and rhombohedral phases reveal a short-range and/or partial ordering of the B-sites. In addition, domains and columnar grains are found in the films. Our results demonstrate that the phase and microstructure of the La2NiMnO6 films can be tuned by epitaxial strains induced by different substrates.

B-site ordering and strain-induced phase transition in double-perovskite La2NiMnO6 films

“…Additionally, in comparison with the partially disordered LNMO films grown at 800 °C 26 , the LNMO films prepared at 900 °C exhibit a long-range B-site ordering. In fact, with the exception of the growth temperature, the deposition conditions were held the same for preparing LNMO films in these two works.…”

“…in the LNMO/STO and LNMO/LSAT systems 26 . In most cases, with the increase of the film-substrate lattice mismatch, apart from the formation of oriented domains in the LNMO films misfit dislocations appear at the film-substrate interface, contributing to misfit strain relaxation.…”

“…It is noted that in comparison with the significant studies on the synthesis and properties of bulk materials 1,6,13,18,36,37 , there was a lack of information on the ordering of B-site in double-perovskite films related to the growth parameters and the epitaxial strain induced structure evolution. In our previous work, the short-range ordering of the B-site cation was obtained in the LNMO films coherently grown on the perovskite-type STO and LSAT substrates at 800 °C 26 . Nevertheless, phase stability of LNMO films related to the strain relaxation and the effect of film-growth temperature on the chemical ordering of B-site cations in LNMO films are less concerned.…”

“…In addition, the epitaxial strain of thin films affects the microstructural and physical properties of the films 26–35 . R. J. Zeches et al .…”

Microstructure and electrical conductivity of (Y, Sr)CoO 3-δ thin films tuned by the film-growth temperature

“…the angle 2θ of 11.5°, 34.9° and 60.2°, as indicated by vertical red arrows. Based on all of the diffraction peaks, the out-of-plane lattice parameter of the YSCO films grown at 900 °C can be determined to be 0.7652 nm, which is smaller than two times of the lattice parameter of LAST (a=0.3868 nm) [28]. It is noted that no powder diffraction standard data are available for the Y x Sr 1−x CoO 3−δ (x=0.25) bulk.…”