Radio Frequency Sputter Deposition of Epitaxial Nanocrystalline Nd<sub>1-</sub><i><sub>x</sub></i>Sr<i><sub>x</sub></i>CoO<sub>3</sub> Thin Films

In this paper we report the deposition of epitaxial thin films of Nd<sub>1-</sub><i><sub>x</sub></i>Sr<i><sub>x</sub></i>CoO<sub>3</sub> with <i>x </i>= 0, 0.2, and 0.5 on single-crystalline substrates (SrTiO<sub>3</sub> and LaAlO<sub>3</sub>) carried out by means of rf-magnetron sputtering. The deposited films are all completely oriented and epitaxial and characterized by a nanocrystalline morphology. As-deposited films have an average roughness around 1 nm while after the thermal treatment this increases up to 20 nm while preserving the nanocrystalline morphology. All the films deposited on SrTiO<sub>3</sub> have shown to be under a certain degree of tensile strain while those on the LaAlO<sub>3</sub> experience a compressive strain, thus suggesting that at about 50 nm the films are not fully relaxed, even after the thermal treatment. For the <i>x </i>= 0.2 composition three different thicknesses have been investigated, revealing an increased strain for the thinner films.