The study investigates the magnetic order and superconductivity in iron-based layered La(O1-xFx)FeAs systems, focusing on the parent compound LaOFeAs. The research reveals that LaOFeAs exhibits a spin-density-wave (SDW) instability below 150 K, which is suppressed by doping with fluorine to form superconductivity. Neutron scattering data show an abrupt structural distortion from tetragonal to monoclinic symmetry at low temperatures, followed by the development of long-range SDW-type antiferromagnetic order at ~134 K. The magnetic structure is consistent with theoretical predictions, but the observed Fe moment is smaller than expected. The findings suggest that the superconducting regime in these materials occurs near a long-range ordered antiferromagnetic ground state, similar to high-Tc copper oxides. This work highlights the importance of understanding the relationship between magnetism and superconductivity in these new classes of materials.The study investigates the magnetic order and superconductivity in iron-based layered La(O1-xFx)FeAs systems, focusing on the parent compound LaOFeAs. The research reveals that LaOFeAs exhibits a spin-density-wave (SDW) instability below 150 K, which is suppressed by doping with fluorine to form superconductivity. Neutron scattering data show an abrupt structural distortion from tetragonal to monoclinic symmetry at low temperatures, followed by the development of long-range SDW-type antiferromagnetic order at ~134 K. The magnetic structure is consistent with theoretical predictions, but the observed Fe moment is smaller than expected. The findings suggest that the superconducting regime in these materials occurs near a long-range ordered antiferromagnetic ground state, similar to high-Tc copper oxides. This work highlights the importance of understanding the relationship between magnetism and superconductivity in these new classes of materials.