Neutron Diffraction study of Ru doping in Pr$_{0.5}$Ca$_{0.5}$Mn$_{1-x}$Ru$_{x}$O$_{3}$ (x $\le $ 0.10)

Small amount of Ru substitution ($<$10 {\%}) for Mn in charge-ordered manganites destroys charge-ordering (CO) and induces ferromagnetic metallic state. To probe the dramatic role played by Ru in preventing the CO state, we have carried out neutron diffraction studies of Pr0.5Ca0.5Mn1-xRuxO3 compounds (x = 0.0, 0.05 and 0.10) in the temperature range 300-10 K. Evolution of lattice parameters with temperature points out that lattice distortion which accompanies charge ordering disappears on Ru doping. Also Ru doping alters the MnO$_{6}$ octahedron shape from 4-long/2-short type to 2-long/4-short type that suppresses the antiferromagnetic ordering and hence induces ferromagnetism through double exchange interactions. The local structure of x = 0, 0.05 and 0.10 compositions were analyzed using Pair Distribution Function (PDF) at 295 K and 15 K.