Thickness dependence of microstructure in thin La0.7Sr0.3MnO3 films grown on (100) SrTiO3 substrate

authors	Vaghefi, PM; Baghizadeh, A; Willinger, MG; Pereira, MJ; Mota, DA; Almeida, BG; Moreira, JA; Amaral, VS
nationality	International
journal	JOURNAL OF PHYSICS D-APPLIED PHYSICS
author keywords	manganite thin film; pulsed laser deposition; epitaxial growth; columnar structure
keywords	COLOSSAL MAGNETORESISTIVE MANGANITES; PULSED-LASER DEPOSITION; DOMAIN-WALLS; EPITAXY; HETEROSTRUCTURES; DISTORTIONS; OXIDE
abstract	This study investigates the nanostructure of perovskite thin films, and its influence on magnetic properties. Epitaxial thin films of perovskite La0.7Sr0.3MnO3 with thickness ranging from 13.5 nm to 320 nm were deposited on SrTiO3 (1 0 0) substrates using pulsed laser deposition techniques. X-ray diffraction, along with high-resolution transmission electron microscopy (HRTEM) investigations were carried out, and showed the presence of a second, La-rich phase in thick film. Scanning electron microscopy analysis showed thinner films to have smooth surfaces, while thicker films presented large triangular shapes emerging out of the film surface. Also HRTEM images revealed epitaxial growth for thinner films. Thicker films grow with numerous misfit dislocations leading to columnar structure, where the thickest film presents branched structure with an intermediate La-rich layer. Lattice mismatch, diffusion of Mn ions into the substrate and substituting Ti ions are known as sources of strain in films near interfaces. Magnetic properties in the structure mentioned are described by double-exchange interaction, which is very sensitive to local structure. Hence, the nanostructure of films reported here has a remarkable effect on their magnetic properties.
publisher	IOP PUBLISHING LTD
issn	0022-3727
year published	2017
volume	50
issue	39
digital object identifier (doi)	10.1088/1361-6463/aa80bf
web of science category	Physics, Applied
subject category	Physics
unique article identifier	WOS:000409031800001