Pulsed reactive crossed beam laser ablation of La0.6Ca0.4CoO3 using 18O

Abstract

Abstract The composition of thin perovskite films, especially the oxygen content, is a crucial parameter which influences many physical properties, such as conductivity and catalytic activity. Films produced by pulsed laser deposition are normally annealed in an oxygen atmosphere after deposition to achieve a desired oxygen content. In pulsed reactive crossed beam laser ablation, no annealing step is necessary, but a fundamental question regarding this deposition technique is still open: where does the oxygen in the films come from? There are three possibilities, i.e. from the target, from the gas background, or from the gas pulse. To answer this question two experiments were performed: 18 O 2 was used during the deposition process as background gas with 16 O anions in the target and 16 O 2 gas pulse, and a 18 O 2 gas pulse with 16 O from the target and background. These experiments revealed that the quantification of the oxygen origin is only possible, when no oxygen exchange occurs at the deposition temperature. The films are characterized after deposition by elastic recoil detection analysis (ERDA) to determine the 16 O/ 18 O ratio. Experiments with different oxidizing species in the gas pulse (N 2 O and O 2 ) confirm that the oxidizing potential (N 2 O > O 2 ) as well as the number of molecules are important.