Magnetic behavior in the La0.7Pb0.3Mn1−xCoxO3 perovskite compounds

Compositions with the rhombohedral structure have been successfully synthesized in the La 0.7 Pb 0.3 Mn 1-x Co x O 3 system. DC magnetization and AC susceptibility measurements were carried out for the entire series. The Curie temperature T c decreases with increasing x from 306 K (x = 0.0) down to 60 K (x = 0.9). The antiferromagnetic state was found near the Co-rich side (x = 1.0). Co doping tends to destroy the double exchange in Mn 4+ -O-Mn 3+ and broadens the coexistence region of the cluster-glass and ferromagnetic states.