Relationship between T_c and σ J in Doped Superconducting Copper Oxides

A relation of T_c ~σ.Jⁿ proposed after analysing the phase diagram and magnetic susceptibility experiments for La_2-xSr_xCuO₄ and Bi_2+xSr₂Ca_1-xCu₂O_y . This empirical rule agrees with the phase diagram for La_2-xSr_xCuO₄. We suggest that it should also hold for other superconducting cuprites.