Investigations on the Electronic Excitations through Spectroscopic Measures for Resistive Switching Character of Manganite Thin Films

Abstract

Herein, an enhancement in the resistive switching of Y0.95Sr0.05MnO3 (YSMO) films by swift heavy ion (SHI) irradiation­induced electronic excitations is shown. YSMO films are prepared by pulsed laser deposition on a single­crystalline Si substrate. For electronic excitations, Ag15+ ions with 200？MeV energy are used with ion fluences of 1？×？1011 (YS1), 1？×？1012 (YS2), and 1？×？1013 (YS3) ions per cm2. X­ray diffraction shows increase in tensile strain up to YS2 film followed by strain relaxation in YS3 film. Red shifting of Raman active modes signifies the phonon softening due to tensile strain in pristine (YSP) to YS2 films. Atomic force micrographs show that the number and size of defects are increased, indicating the irradiation­induced defect formation, which is suppressed for the YS3 film. Rutherford backscattering spectrometry demonstrates decreased oxygen peak intensities for YS1 and YS2 films, denoting increased oxygen vacancies. Near­edge X­ray absorption fine structure displays a reduction in Mn valence state from Mn4+ to Mn3+, signifying the formation of oxygen vacancies for films up to YS2. The enhancement of resistive switching is governed by tuning the SHI­induced oxygen vacancies. The present study demonstrates that YSMO films are suitable as emerging candidates in memory device applications.