  Incommensurate (IC) charge-order (CO) and spin density wave (SDW) order in
electron doped SrMn1-xWxO3-{\delta} (x= 0.08 to 0.1875) have been studied using
neutron diffraction.The study highlights the drastic effect of electron doping
on the emergence of magnetic ground states which were not revealed in
manganites before. With increasing (x) the crystal structure changes from
simple tetragonal (P4/mmm) to an IC-CO modulated structure with super
space-group P2/m({\alpha}\b{eta}0)00 having ab-planer ferro order of 3dx2-y2
orbitals in a compressed tetragonal (c<a) lattice. The IC-CO order is found to
be intimately related with the 3dx2-y2 orbital order.The occurrence of IC-CO
has been attributed to the mixed character (itinerant/localized) of
eg-electrons undergoing Fermi-surface nesting of 3dx2-y2 band causing
electronic instability, which opens a gap through a charge density wave (CDW)
mechanism. This feature appears to share proximity with the high-Tc cuprates.
At lower temperatures, the CDW phase undergoes SDW transition, which changes
continuously with x and finally disappear at higher x due to the introduction
of large frustration into the system. For 0.08 < x < 0.10 a C-type
antiferromagnetic (AFM) order with propagation vector k = (1/2, 1/2, 0) appears
under ferro-ordering of 3dz2 orbitals, whereas for x > 0.1, a different C-type
AFM order with propagation vector k = (1/2,0,1/2), coexists with an
incommensurate SDW order with k = (0.12, 0.38, 1/2).For compositions with
0.1625 < x < 0.175, while the structural features of CDW and orbital-order
remain qualitatively the same, the magnetic interaction gets modified and
results another SDW phase with single incommensurate propagation vector k =
(0.07, 0.43, 1/2). A detail magnetic and structural phase-diagram, as a
function of W substitution for SrMn1-xWxO3 (0.08 < x < 0.4) is presented.
