The crystal and magnetic structure of polycrystalline La_0.5–xNd_xCa_0.5MnO₃ (0.0≤x≤0.5) samples have been investigated using magnetization, resistivity, transmission electron microscope, and neutron  diffraction techniques. The samples are iso structural and possess ortho rhombic structure in Pnma space group. On lowering of temperature, the samples exhibit CE-type anti ferro magnetic structure coexisting with a weak  ferro magnetic ordering. The charge and orbitally ordered anti ferromagnetic phase is weakened by the growth of ferro magnetic phase. The evolution of structura ldistortions and magnetic structure at low temperature as a function of Nd doping exhibit a strong correlation with A-site disorder (σ²).