Chemical solution growth of La₀.₇Sr₀.₃MnO₃ nanotubes in confined geometries

Abstract

Self-standing La₀.₇Sr₀.₃MnO₃ nanotubes with outer diameter ranging from 100 to 200 nm have been successfully synthesized by template assisted chemical solution deposition using nanoporous anodized alumina membranes of varying pore size. This template synthetic strategy provides rather monodisperse size distributed nanotubes. A sol–gel based polymer precursor route was used to fill the porous membranes and a subsequent heat treatment (700–1,000 C) enabled the phase formation and crystallization of the nanotubes. A good control over viscosity, stoichiometry and stability of the precursor solution were identified as crucial parameters for the template aided synthesis. The synthesized La₀.₇Sr₀.₃MnO₃ nanotubes are polycrystalline and ferromagnetic with a Curie temperature of 350 K. Control over the nanowall thickness is attained by varying template filling time which is corroborated by magnetic moment results.