1 Thermoanalytical study of the decomposition of yttrium trifluoroacetate thin films 1 2 3 H. Eloussifi 1,2 , J. Farjas 1, , P. Roura 1 , S. Ricart 3 , T. Puig 3 , X. Obradors 3 and M. Dammak 2 4 1 GRMT, GRMT, Department of Physics, University of Girona, Campus Montilivi, E17071 5 Girona, Catalonia (Spain) 6 2 Laboratoire de Chimie Inorganique, Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 7 3000 Sfax, Tunisia 8 3 Institut de Ciència de Materials de Barcelona (CSIC), Campus UAB, 08193 Bellaterra, 9 Catalonia, Spain 10 11 12 Abstract 13 We present the first use of the thermal analysis techniques to study yttrium trifluoroacetate thin 14 films decomposition. In situ analysis was done by means of thermogravimetry, differential 15 thermal analysis, and evolved gas analysis. Solid residues at different stages and the final product 16 have been characterized by X-ray diffraction and scanning electron microscopy. The thermal 17 decomposition of yttrium trifluoroacetate thin films results in the formation of yttria and presents 18 the same succession of intermediates than powder’s decomposition, however, yttria and all 19 intermediates but YF 3 appear at significantly lower temperatures. We also observe a dependence 20 on the water partial pressure that was not observed in the decomposition of yttrium 21 trifluoroacetate powders. Finally, a dependence on the substrate chemical composition is 22 discerned. 23 24 25 Keywords: thermal analysis, thin films, yttrium trifluoroacetate, yttria, thermal decomposition. 26 27 28 29