Strain engineering of functional properties in epitaxial thin films of strongly correlated oxides exhibiting octahedral-framework structures is hindered by the lack of adequate misfit relaxation models. Here we present unreported experimental evidence of a four-stage hierarchical development of octahedral-framework perturbations resulting from a progressive imbalance between electronic, elastic, and octahedral tilting energies in La(0.7)Sr(0.3)MnO(3) epitaxial thin films grown on SrTiO(3) substrates. Electronic softening of the Mn-O bonds near the substrate leads to the formation of an interfacial layer clamped to the substrate with strongly degraded magnetotransport properties, i.e., the so-called dead layer, while rigid octahedral tilts become relevant at advanced growth stages without significant effects on charge transport and magnetic ordering.

The search for new strategies to enhance the oxide ionic conductivity in oxide materials is a very active field of research. These materials are needed for application in a new generation of more

A systematic study of the growth process of LaMnO 3 (LMO) thin films, by pulsed laser deposition, on top of SrTiO 3 substrates under different oxygen partial pressures (PO 2) is reported. It is found that the accommodation of the orthorhombic LMO phase onto the cubic STO structure, i.e. the amount of structural strain, is controlled by background oxygen pressure. We demonstrate that magnetic behaviour can be continuously tuned from robust ferromagnetic (FM) ordering to an antiferromagnet. These results strongly point to a strain-induced selective orbital occupancy as the origin of the observed FM behaviour, in agreement with recent theoretical calculations.

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