Correlated magnetism in low-doped manganites

Abstract In this article, resonant and high-energy X-ray diffraction studies together with magnetization and transport measurements on lightly doped manganites will be presented. The main focus is put on the metal–insulator transition in La 1 - x Sr x MnO 3 with 0.10 x 0.15 and, in particular, on the stabilization of the ferromagnetic insulating (FMI) phase of these compounds. The experimental results reveal an orbital rearrangement at the metal–insulator transition which is tightly connected to the magnetic degrees of freedom. More precisely, the double exchange mechanism is found to be essential for the stabilization of the FMI phase. This conclusion is further supported by the studies on ( La 1 - y Pr y ) 7 / 8 Sr 1 / 8 MnO 3 and the layered compound La 7 / 8 Sr 9 / 8 MnO 4 .