Structure and Properties of Double Perovskite System La\(_2\)Co\(_{1-x}\)Fe\(_{x}\)MnO\(_{6}\)

Low Fe-doped insulating ferromagnets La$_2$CoMnO$_6$ were prepared and studied. The compounds crystallized in orthorhombic space group Pnma with slight changes in the lattice constants. We have observed a significant reduction of resistivity due to doping, together with an increase of magnetization and saturated magnetization as doping level increased. The doping also reduced $T_C$ for both transitions at around 220 and 140 K which attribute for the different spin orderings of the magnetic ions. The small features were also seen at around 40 K and should correspond to the cluster glassy region with spin disorders.