1 research outputs found
Phase Control in Thin Films of Layered Cuprates
Perovskite-related
layered cuprates are considered the basis of
all high-<i>T</i><sub>c</sub> superconductors. Considerable
effort has been put into understanding these materials. Deposition
of phase-pure and oriented thin films can help shed light on the unusual
interplay between the structure and properties, as the copper layers
will be oriented in the same direction throughout the sample. Chemical
deposition routes have been considered difficult, because of detrimental
decomposition of metalorganic precursors, catalyzed by deposited copper
species. In the current paper, we present a route for atomic layer
deposition (ALD) of layered lanthanum cuprates. The system exhibits
remarkable stoichiometric control, enabling deposition of a variety
of lanthanum cuprate species. La<sub>2</sub>CuO<sub>4</sub> films
is shown to be tetragonal and (001) oriented on LaAlO<sub>3</sub> (100)<sub>pc</sub>, with the copper planes parallel to the film surface. We
go on to demonstrate that the oxygen-stoichiometry of LaCuO<sub>3–<i>x</i></sub> films can be tuned by post-treatment, resulting
in phase control of the complex perovskite lanthanum cuprate system.
Epitaxial films have been obtained for oxygen annealed monoclinic
and air annealed orthorhombic variants of LaCuO<sub>3–<i>x</i></sub> on LaAlO<sub>3</sub> (100)<sub>pc</sub> substrates
with a LaCuO<sub>3–<i>x</i></sub>(100)|[640]||LaAlO<sub>3</sub>(100)<sub>pc</sub>|[310]<sub>pc</sub> and LaCuO<sub>3–<i>x</i></sub>(100)<sub>pc</sub>|[110]<sub>pc</sub>||LaAlO<sub>3</sub>(100)<sub>pc</sub>|[110]<sub>pc</sub> epitaxial relationship,
respectively