ANTIFERROMAGNETIC METALLIC STATE IN DOPED MANGANITES

Electronic and magnetic properties are systematically investigated for doped manganites R1(1-x)Sr(x)MnO(3) (R = La1-zNdz) by changing the no minal hole concentration x and the averaged ionic radius of the perovs kite A site (z), or the one-electron bandwidth W. In the heavily doped region (x greater than or equal to 0.50), we observed a layered-type (A-type) antiferromagnetic state with metallic conductivity (rho appro ximate to 4X10(-4) Omega cm at 5 K for La0.46Sr0.54MnO3). This observa tion suggests that the antiferromagnetic metallic (AFM) state is the a lternative ground state for doped manganites, besides the ferromagneti c metallic (FM) state.