Journal de Physique IV

J. Phys. IV France 118 (2004) 165-171
DOI: 10.1051/jp4:2004118020

Sodium doped lanthanum manganites thin films: Influence of the oxygen content on the structural parameters

I. Alessandri¹, E. Bontempi¹, L. Sangaletti², S. Pagliara², L. Malavasi³, F. Parmigiani², G. Flor³ and L. E. Depero¹

¹ INSTM and Laboratorio di Strutturistica Chimica, Università di Brescia, via Branze 38, 25123, Brescia (Italy)
² INFM and Dipartimento di Fisica, Università Cattolica del Sacro Cuore, via Musei 41, 25121, Brescia (Italy)
³ INSTM and Dipartimento di Chimica-Fisica "M.Rolla", Università di Pavia, v.le Taramelli 16, 27100, Pavia (Italy)

Abstract
We report the structural characterisation of La $_{\rm 1-x}$ Na $_{\rm x}$ MnO $_{3+\delta}$ thin films deposited by Rf-magnetron sputtering onto SrTiO ₃ (100) single crystal substrates. In particular, we focussed our attention on a series of samples annealed at different pO ₂, ranging from 1 to 10 ^-6 atm. XRD and microRaman data show an expansion of the perovskite lattice for samples annealed in reducing conditions. This results agree with general manganite gas-solid equilibrium involving the formation of Mn ⁴⁺as the oxygen content increases. For pO $_\,10^$ atm the structure rearranges because of the increasing the oxygen vacancies and the volume of the unit cell shrinks.