Competition between the antiferromagnetic charge-ordered and ferromagnetic states in doped manganites

Structural and magnetic properties are systematically investigated for filling- and structure-controlled manganites (La1-zNdz)(1-x)CaxMnO3 (0.35 less than or equal to x less than or equal to 0.50, 0.0 less than or equal to z less than or equal to 1.0). The ground state at a fixed x value was found to change from ferromagnetic metallic (FM) to charge-ordered insulating (CO) states with increase of z. We have found suppressed ferromagnetic moment (similar to 0.5 mu(B) - 2.5 mu(B) at 1 T) at 10 K in the vicinity of the FM-CO phase boundary, and have ascribed it to the phase separation (PS) into the FM and CO states. The PS region spreads out around the FM CO phase boundary in the ground-state phase diagram. [S0163-1829(99)04634-2].