Suppression of the ferromagnetic state in LaCoO3 films by rhombohedral distortion

Abstract

Epitaxially strained LaCoO3 (LCO) thin films were grown with different film thickness, t, on (001) oriented (LaAlO3)0.3(SrAl0.5Ta0.5O3)0.7 (LSAT) substrates. After initial pseudomorphic growth the films start to relieve their strain partly by the formation of periodic nano-twins with twin planes predominantly along the <100> direction. Nano-twinning occurs already at the initial stage of growth, albeit in a more moderate way. Pseudomorphic grains, on the other hand, still grow up to a thickness of at least several tenths of nanometers. The twinning is attributed to the symmetry lowering of the epitaxially strained pseudo-tetragonal structure towards the relaxed rhombohedral structure of bulk LCO. However, the unit-cell volume of the pseudo-tetragonal structure is found to be nearly constant over a very large range of t. Only films with t > 130 nm show a significant relaxation of the lattice parameters towards values comparable to those of bulk LCO.

31 pages, 10 figures

Cited by in corpus (8)

• Strain-Induced Spin States in Atomically Ordered Cobaltites
• Structural effects on the spin-state transition in epitaxially strained LaCoO${}_3$ films
• First-principles study of intermediate-spin ferrous iron in the Earth's lower mantle
• The unusual magnetism of nanoparticle LaCoO3
• Tunable Ferromagnetism in LaCoO3 Epitaxial Thin Films
• Room-Temperature Valence Transition in a Strain-Tuned Perovskite Oxide
• The effects of Co3O4 on the Structure and Unusual Magnetism of LaCoO3
• Channelling study of La${}_{1-x}$Sr${}_x$CoO${}_3$ films on different substrates