We describe the details of single crystal growth of $Ca_2RuO_4$ by a floating zone method. The $Ca_2RuO_4$ is an antiferromagnetic insulator with a Neel temperature at $T_N=110K$ and a Mott transition at $T_MI=357K$. $Ca_2RuO_4$ was synthesized in two different modification whose crystal structure was closely related. Both structures are derived from the ideal $K_2NiF_4$ structure type by a rotation of the $RuO_6$ octahedra around the long axis, combined with a tilt around an axis lying in the $RuO_2$ plane. For the growth of $Ca_2RuO_4$ single crystals, polycrystalline feedrods were prepared from powder mixtures of $CaCO_3$ and $RuO_2$ with mole ratio of 1:1, 1:1.15, 1:1.3 and 1:1.5, calcined at 1360℃ for 12h and sintered at 1000℃ for 12h. And we succeeded in synthesizing polycrystalline samples. Slight substitution of trivalent Nd for divalent Ca in $Ca_2RuO_4$ not only drastically reduces but also simultaneously precipitate robust ferromagnetism in the antiferromagnetic host. It is believed that the ferromagnetic behavior is closely associated with the kinetic energy of the electron added from the Nd ion that modies the magnetic structure.
