Self-organization of epitaxial La_0.35Pr_0.275Ca_0.375MnO₃ manganite nanorods on NdGaO₃ substrates

Abstract

We studied the structure, morphology, and growth mechanism of self-organized La_0.35Pr_0.275Ca_0.375MnO₃ manganite nanorods grown on NdGaO₃ substrates by pulsed-laser deposition. A two-layered structure was revealed: the first layer, about 120 nm thick, was formed via layer-by-layer two-dimensional (2D) growth; the second layer consisted of a three-dimensional assembly of nanorods lying perpendicular to the 2D layer. The nanorods, averaging 50 nm across and 180 nm long, exhibited six crystallographic orientational domains, but only two predominated, both with their b axis lying parallel to that of substrate (parallel to the film normal) and with an in-plane a- and c-axis interchange to minimize local lattice mismatch. We consider that the formation of such self-assembled nanorods is related to the Stranski-Krastanov growth mode and discuss the associated energy terms of such growth based on density functional theory calculations.