Synthesis and characterisation of La1−xNaxMnO3+δ thin films manganites

Optimally sodium doped lanthanum manganite (LNMO) thin films have been grown onto differently oriented NdGaO3 single crystals substrates by means of radio-frequency (RF)-magnetron sputtering technique, in order to investigate the role of the strain imposed by lattice mismatch on the magnetotransport properties. Films deposited onto NdGaO3 (110) experiment a slight in-plane compressive strain that can be tuned by the thickness and allows to achieve colossal magnetoresistive effects. On the contrary, the change of the substrate orientation induces an in-plane tensile strain, making the film insulating. Above observations are explained by considering the effect of distortions of the MnO coordination polyhedra.