Substrate dependent strain effect on surface morphology of nano-structured manganite thin films [La0.5Pr0.2Sr0.3MnO3 (LPSMO)] grown by pulsed laser deposition
J. H. Markna
Volume 3, Issue 1, Page 17-21, Year 2018 | DOI: 10.5185/amp.2018/678
Keywords: Nanostructured thin film, surface morphology, pulsed laser deposition, AFM, mismatch.
Abstract: In the present communication, nanostructured (50nm) La0.5Pr0.2Sr0.3MnO3 (LPSMO) manganite thin epitaxial films were synthesized on polished (h00) oriented SrTiO3 [STO] and LaAlO3 [LAO] single crystal substrates using high energy laser based deposition technique. In the present study, Q-switched 3rd harmonic (355nm) Nd: YAG solid-state laser (6 ns)[Laser energy = 2.17 J/cm2with10 Hz repetition rate] was used to deposit nanostructured manganite thin films. The surface morphological analysis of grown LPSMO nanostructured thin films was doing by the AFM (Atomic Force Microscopy) measurements, while strain measurement and calculation was carried out using XRD technique. Here, use of theSrTiO3 substrate for the deposition resulting in the tensile strain whereas use of LaAlO3 substrate responsible for the compressive strain inside thenanostructure LPSMO epitaxial layer at the interface. The positive (+) values of mismatch at interface (based on structural parameters) demonstrating the tensile strain in LPSMO/SrTiO3 thin film ( ~ 1.00 % ) with 50nm thickness, while anegative value of the mismatch corresponding to the large compressive strain at the interface in the case of LPSMO/LaAlO3 film( ~ -2.56 %) with same thickness. Such massive and substrate dependent opposite strain at interface affect the surface morphology. AFM images clearly indicate that LPSMO nanostructured film deposited on the SrTiO3 substrate possesses the formation of small speck (grains) as compared to thin film grown on the LaAlO3 substrate. Copyright © 2018 VBRI Press.