Thin films of La0.67Ba0.33MnO3 were deposited on NdGaO3 by pulsed laser deposition with in situ RHEED diagnostics. A strong dependence of structural and electrical transport properties of the films on the background oxygen pressure was observed. Electrical resistance versus temperature and X-ray diffraction measurements were used to characterise the deposited films. Deposition at low background oxygen pressure (approximate to 10(-1) Pa) resulted in a good structural quality with an atomically flat surface, but poorer transport properties compared to films grown at higher pressure (approximate to 50 Pa). These observations have been correlated with the characteristics of the plume expansion by studying pulsed laser ablation of manganate samples into oxygen background gas by optical emission spectroscopy and ion probe diagnostics. These studies have been carried out using the parent LaMnO3 compound as target material in presence of an oxidizing atmosphere. (c) 2005 Elsevier B.V. All rights reserved.