Effects of swift heavy ion irradiation on La0.5Pr0.2Sr0.3MnO3 epitaxial thin films grown by pulsed laser deposition

We report the observation of room temperature insulator to metal transition and magnetoresistance characteristics of Swift Heavy Ions (SHIs) irradiated La0.5Pr0.2Sr0.3MnO3 (LPSMO) epitaxial thin films grown on single crystal (10 0) SrTiO3 substrates using Pulsed Laser Deposition. The epitaxial nature and crystallanity of the films was confirmed from the structural and magneto re si stance characteristics. Irradiation with the 200 MeV Ag15+ ions at a fluence of about 5 x 10(11) ions/CM2 showed suppression in the resistivity by similar to 68% and 31% for the films with 50 nm and 100 nm thickness respectively. The possible reasons for this suppression could be either release of strain in the films in the dead layer at the interface of film-substrate or Swift Heavy Ions induced annealing which in turn affects the Mn-O-Mn bond angle thereby favoring the Zener double exchange. Field Coefficient of Resistance (FCR) values for both films, determined from R-H data and magneto resistance data, showed a marginal enhancement after irradiation. (c) 2007 Elsevier B.V. All rights reserved.