Vertical (La,Sr)MnO₃ Nanorods from Track‐Etched Polymers Directly Buffering Substrates

Abstract

A novel and general methodology for preparing vertical, complex‐oxide nanostructures from a sol–gel‐based polymer‐precursor solutions is developed using track‐etched polymers directly buffering substrates. This method is able to develop a nanostructure over the entire substrate, the dimensions and localization of the vertical nanostructures being preset by the polymeric nanotemplate. Thereby, nanostructures with lateral sizes in the range of 100 to 300 nm and up to 500 nm in height have been grown. Two examples are presented herein, the latter being the evolution of the initial, metastable nanostructure. Specifically, La0.7Sr0.3MnO3 polycrystalline rods are grown at mild temperatures (800 °C); upon strong thermal activation (1000 °C) they suffer a profound transformation into vertical, single‐crystalline (La,Sr)xOy nanopyramids sitting on a La0.7Sr0.3MnO3 epitaxial wetting layer. The driving force for this outstanding nanostructural evolution is the minimization of the total energy of the system, which is reached by reducing the grain‐boundary, total‐surface, and strain‐relaxation energies. Finally, advanced electron‐microscopy techniques are used to highlight the complex phase separation and structural transformations occurring when the metastable state is overcome.

Dual Function Polyvinyl Alcohol Based Oxide Precursors for Nanoimprinting and Electron Beam Lithography

“…The absence of manganese in the nanodots indicates that the generated nanostructures were actually not LSMO, rather a lanthanum strontium oxide. This was not a wholly unexpected result due to other reported work showing the migration of manganese out of LSMO nanostructures [3]. The possibility that manganese is lost during the electron beam writing process, or the developing step should also be considered, and is under study.…”

“…Since many functional properties rely on epitaxial order and crystal orientation (e.g., piezoelectric and high-T C superconducting properties), growth methods that are able to provide ordered arrays of epitaxial nanostructures are highly interesting. Several recent studies in our group have grown epitaxial single crystalline functional oxide nanostructures on single crystal substrates [3][4][5]. However, these nanostructures were generated with no precise position control.…”

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

“…Otherwise, when the fluid is a polymer solution of high viscosity, a wall wetting process occurs, giving rise to nanotubes formation upon solvent evaporation and crystallization at high temperatures, as in the present system. However, we recently showed that the same precursor solution may have a very different wetting behaviour when filling track etched porous polymer templates with low surface tension, there giving rise to the formation of nanorods [11][12][13].…”

“…[1][2][3][4]. Recently, increasing efforts have been made to synthesize and understand the growth of one-dimensional nanostructures, such as nanotubes and nanowires of these materials due to their promising potential applications in spintronics, transducers or sensors in future nanoscale devices while retaining unique properties due to size confinement in the radial direction [5][6][7][8][9][10][11][12][13].…”

Optimization of the TFA-MOD Process for Introduction of ${\rm BaZrO}_{3}$ Pinning Centers in YBCO Films

“…For correlated pinning, extended defects of controlled orientation are preferred, and in particular for YBCO, c-axis pinning is of particular interest as this field orientation typically determines the minimum in-field , which is a limiting factor for many applications. Several approaches to introduce pinning sites ex-situ have been investigated, such as heavy ion irradiation [5] and nanorod deposition on substrates prior to YBCO deposition [6]. On the other hand, in-situ techniques most frequently involve precipitation of second phase particles, by varying the YBCO stoichiometry or introducing other rare-earth elements [7], formation of self-assembling precipitates [8], addition of nano-sized secondary particles [9]- [11] or interlayer formation [12].…”