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G. Franceschi, M. Schmid, U. Diebold, M. Riva:
"Atomically resolved surface phases of La_0.8Sr_0.2MnO₃(110) thin films";
Journal of Materials Chemistry A, 8 (2020), 22947 - 22961.

The atomic-scale properties of lanthanum-strontium manganite (La1 xSrxMnO3 d, LSMO) surfaces are of
high interest because of the roles of the material as a prototypical complex oxide, in the fabrication of
spintronic devices and in catalytic applications. This work combines pulsed laser deposition (PLD) with
atomically resolved scanning tunneling microscopy (STM) and surface analysis techniques (low-energy
electron diffraction - LEED, X-ray photoelectron spectroscopy - XPS, and low-energy He+ ion
scattering - LEIS) to assess the atomic properties of La0.8Sr0.2MnO3(110) surfaces and their dependence
on the surface composition. Epitaxial films with 130 nm thickness were grown on Nb-doped SrTiO3(110)
and their near-surface stoichiometry was adjusted by depositing La and Mn in sub-monolayer amounts,
quantified with a movable quartz-crystal microbalance. The resulting surfaces were equilibrated at
700 C under 0.2 mbar O2, i.e., under conditions that bridge the gap between ultra-high vacuum and the
operating conditions of high-temperature solid-oxide fuel cells, where LSMO is used as the cathode. The
atomic details of various composition-related surface phases have been unveiled. The phases are
characterized by distinct structural and electronic properties and vary in their ability to accommodate
deposited cations.

http://dx.doi.org/10.1039/d0ta07032g