We report the effect of 200 MeV Ag15+ ion irradiation with fluence of similar to 5 x 10(11) ions/cm(2) on the structure and surface morphology of thin film devices of La0.6Pr0.2Sr0.2MnO3 (named as LPSMO) (p)/SrNb0.2Ti0.8O3 (named as SNTO) (n) manganite grown by Pulsed Laser Deposition (PLD) technique. The n-type manganite layers studied were of thickness 50, 100 and 200 nm. After ion irradiation, the structural studies revealed improved crystallinity in the LPSMO/SNTO devices with the thickness of 50 and 200 nm. But the 100 nm films showed the formation of regular tracks like feature in their surface morphology after irradiation. All the irradiated films show suppression of resistivity at all the temperatures but it was different rate in 100 nm LPSMO films which may be attributed to the formation of linear track like defects. (C) 2011 Elsevier B. V. All rights reserved.