La 0.7 Sr 0.3 MnO 3 (LSMO) thin films (with a thickness of 10, 20, 60, 75, and 100 nm) were grown on SrTiO 3 (STO)-buffered silicon (001) substrates by reactive molecular-beam epitaxy. Xray diffraction (XRD) revealed the heterostructures to be fully epitaxial with orientation relationship (001) LSMO jj (001) STO jj (001) Si and [100] LSMO jj [100] STO jj [110] Si. Root mean square roughness was about 0.5 nm as measured by atomic force microscopy (AFM) for films of 10-75 nm thicknesses, and about 1 nm for the 100 nm thick LSMO film.Normalized Hooge parameters in the (0.95 AE 0.25) Â 10 À30 -(3.41 AE 0.71) Â 10 À30 m 3 range were measured at 300 K, which are comparable to the noise level typically measured in the best LSMO films on (001) STO substrates. Overall these very low noise LSMO films with thicknesses in the 10-100 nm range grown on STO/Si showed properties rivaling those of LSMO films deposited on (001) STO single crystal substrates, thus demonstrating their potential use for LSMO-based devices on silicon substrates.

The relation between lattice deformation, dc electrical properties and 1/f noise at room temperature was investigated experimentally in two series of high epitaxial La 0.7 Sr 0.3 MnO 3 (LSMO) thin films of various thicknesses. The first series was deposited on SrTiO 3 (0 0 1) single crystal substrates by pulsed laser deposition and the second one on SrTiO 3-buffered Si (0 0 1) substrates by reactive-molecular-beam epitaxy. A clear correlation was found between 1/f noise level and the temperature of the metal-to-insulator transition. These findings are important in view of the optimization of LSMO thin films for applications in sensors.