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Posted: Mar 04, 2015
Researchers obtain high-quality perovskites over large areas by a chemical method
(Nanowerk News) Chemical methods for thin-film deposition are an affordable and versatile alternative to physical deposition techniques (pulsed laser deposition, sputtering, molecular beam epitaxy, etc.). In particular, deposition from a solution is preferred to avoid the use of high-vacuum chambers, and, a priori, is suitable for coatings over large areas and complex-shaped objects. Among the chemical methods based on a liquid precursor, spray deposition and sol–gel are the most widely used.
However, in spite of the obvious advantages, chemical methods show some serious drawbacks, as poorer control of the thickness and stoichiometry, larger interface and surface roughness, and difficult fabrication of homogeneous films and multilayers over large areas. Consequently, these problems limited the applicability of chemical deposition methods, or their use in highly demanding applications (tunnel junctions, etc.).
LaMnO3 is a Mott insulator, an oxide which gives rise to a very rich electronic and magnetic phase diagram after hole doping, being the parent phase to colossal magnetoresistive oxides. On the other hand, it has been recently identified as one of the most suitable catalysts for electrochemical oxygen reduction reactions (fuel cells) and for the oxidative removal of toluene.
Therefore, it will be very important the development of affordable techniques for deposition of LaMnO3 thin films, with a large surface/volume ratio, and free of defects over large areas. Physical properties of perovskites include superconductivity, magnetoresistance and dielectric properties, which are of great importance in microelectronics and telecommunication.