Strain and magnetism in (La _0.7 Sr _0.3 )MnO ₃ very thin films epitaxially grown on SrTiO ₃

We study the epitaxial growth of (La _0.7 Sr _0.3 )MnO ₃ on SrTiO ₃ by pulsed laser deposition. This paper presents some magnetic and structural properties of these films, with the stress on very thin films (5 and 23nm). We show that such films, although strained, still have a Curie temperature well above 300K. These very thin films keep their properties over measurement periods of several months. A key feature of their microstructure is that it includes rhombohedral distortions of the tetragonal geometry imposed by the epitaxial strain. However, this microstructure appears sensitive to the electron beam of a transmission electron microscope.