Inhomogeneous magnetic behavior of Pr0.7Ca0.3CoO3 and Nd0.7Ca0.3CoO3

Unlike La0.7Ca0.3CoO2.97, Pr0.7Ca0.3CoO3 and Nd0.7Ca0.3CoO2.95 do not show distinct ferromagnetic transitions, but instead they exhibit very low magnetic moments down to 50K. A detail study of magnetic properties of Pr0.7Ca0.3CoO3 and Nd0.7Ca0.3CoO2.95 shows that the materials are inhomogeneous, exhibiting properties similar to those of frustrated magnetic systems. In both these cobaltates, small ferromagnetic clusters seem to be present in an antiferromagnetic host.