Mesoporous Thin Films as Nanoreactors for Complex Oxide Nanoparticle-Based Devices

Abstract

We combine for the first time the properties of ordered mesoporous thin films and complex oxide nanoparticles in the design of heterostructures, taking advantage of the accessible tridimensional pore network. In this work, we demonstrate the feasibility of synthesizing La0.88Sr0.12MnO3 inside the pores of a mesoporous SiO2 thin film, using pulsed laser deposition. In order to understand the filling process, a set of samples were deposited for three different deposition times on mesoporous and nonmesoporous SiO2 substrates. Their structural, magnetic, magnetocaloric, and electrical transport properties were studied. All of the results evidence the presence of the manganite compound inside the pores, which was confirmed by cross-sectional elemental mapping. X-ray reflectometry shows that it is possible to control the filling of the pores, keeping some accessible porosity. The magnetic behavior suggests the presence of weakly interacting ferromagnetic nanoparticles inside the pores. We provide here a successful strategy for the fabrication of complex oxide nanoparticle arrays with highly controlled size and ordering. Their easy incorporation into micro- and nanofabrication procedures unveils direct implications in the field of interfaces and nanoparticle devices as diverse as energy conversion systems, solid oxide fuel cells, spintronics, and neuromorphic memristor networks.