1 research outputs found
Strain-Induced Spin States in Atomically Ordered Cobaltites
Epitaxial strain imposed in complex oxide thin films
by heteroepitaxy
is recognized as a powerful tool for identifying new properties and
exploring the vast potential of materials performance. A particular
example is LaCoO<sub>3</sub>, a zero spin, nonmagnetic material in
the bulk, whose strong ferromagnetism in a thin film remains enigmatic
despite a decade of intense research. Here, we use scanning transmission
electron microscopy complemented by X-ray and optical spectroscopy
to study LaCoO<sub>3</sub> epitaxial thin films under different strain
states. We observed an unconventional strain relaxation behavior resulting
in stripe-like, lattice modulated patterns, which did not involve
uncontrolled misfit dislocations or other defects. The modulation
entails the formation of ferromagnetically ordered sheets comprising
intermediate or high spin Co<sup>3+</sup>, thus offering an unambiguous
description for the exotic magnetism found in epitaxially strained
LaCoO<sub>3</sub> films. This observation provides a novel route to
tailoring the electronic and magnetic properties of functional oxide
heterostructures