A superstructure modulation induced by La doping of the layered manganate LaxSr4−xMn3O10

In this paper, transmission electron microscopy (TEM) has been used for studying the slightly La-doped layered manganate LaxSr4−xMn3O10. Albeit the samples for x ≤ 0.15 appear single phased from the powder X-ray diffraction (XRD) analysis, the presence of numerous modulated domains in them has been revealed by electron diffraction and high-resolution electron microscopy. Electron diffraction data indicate that the local superstructure modulation is two-dimensional, and the modulation plane lies in the ac   plane. The two primary modulation vectors are q1=(1/4)a* and q2=(1/2)c*. High-resolution electron microscopy data suggest that the origin of the modulated structure is possibly attributable to an ordering of the La dopants. The locally modulated structure may have a correlation with the magnetic properties, typical of the ferromagnetic (FM) clusters, of the LaxSr4−xMn3O10 manganate.