E. Karapetrova

Quantifying octahedral rotations in strained perovskite oxide films

We have measured the oxygen positions in

Effect of interfacial octahedral behavior in ultrathin manganite films.

{\text{LaNiO}}_{3}

Control of octahedral rotations in (LaNiO{sub 3}){sub n}/(SrMnO{sub 3}){sub m} superlattices

films to elucidate the coupling between epitaxial strain and oxygen octahedral rotations. The oxygen positions are determined by comparing the measured and calculated intensities of half-order Bragg peaks, arising from the octahedral rotations. Combining ab initio density-functional calculations with these experimental results, we show how strain systematically modifies both bond angles and lengths in this functional perovskite oxide.

Charge transport and magnetization profile at the interface between the correlated metal CaRuO3 and the antiferromagnetic insulator CaMnO3

We investigate structural coupling of the MnO6 octahedra across a film/substrate interface and the resultant changes of the physical properties of ultrathin La2/3Sr1/3MnO3 (LSMO) films. In order to isolate the effect of interfacial MnO6 octahedral behavior from that of epitaxial strain, LSMO films are grown on substrates with different symmetry and similar lattice parameters. Ultrathin LSMO films show an increased magnetization and electrical conductivity on cubic (LaAlO3)0.3(Sr2AlTaO6)0.7 (LSAT) compared to those grown on orthorhombic NdGaO3 (NGO) substrates, an effect that subsides as the thickness of the films is increased. This study demonstrates that interfacial structural coupling can play a critical role in the functional properties of oxide heterostructures.

Microscopic evidence of a strain-enhanced ferromagnetic state in LaCoO3 thin films

Oxygen octahedral rotations have been measured in short-period (LaNiO{sub 3}){sub n}/(SrMnO{sub 3}){sub m} superlattices using synchrotron diffraction. The in-plane and out-of-plane bond angles and lengths are found to systematically vary with superlattice composition. Rotations are suppressed in structures with m > n, producing a nearly unrotated form of LaNiO{sub 3}. Large rotations are present in structures with m < n, leading to reduced bond angles in SrMnO{sub 3}. The metal-oxygen-metal bond lengths decrease as rotations are reduced, in contrast to behavior previously observed in strained, single-layer films. This result demonstrates that superlattice structures can be used to stabilize nonequilibrium octahedral behavior in a manner distinct from epitaxial strain, providing a novel means to engineer the electronic and ferroic properties of oxide heterostructures.

Spatial control of functional properties via octahedral modulations in complex oxide superlattices

A combination of spectroscopic probes was used to develop a detailed experimental description of the transport and magnetic properties of superlattices composed of the paramagnetic metal CaRuO

Elastic anomaly for Sr Ti O 3 thin films grown on Si(001)

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Strain-driven spin reorientation in magnetite/barium titanate heterostructures

and the antiferromagnetic insulator CaMnO

Nanoscale Control of Homoepitaxial Growth on a Two-Dimensional Zeolite

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Octahedral rotation patterns in strained EuFeO 3 and other Pbnm perovskite films: Implications for hybrid improper ferroelectricity

. The charge carrier density and Ru valence state in the superlattices are not significantly different from those of bulk CaRuO