Temperature variation of the magnetic susceptibility χ, resistivity ρ, specific heat C, and lattice constants has been investigated in electron-doped ${\mathrm{CaMnO}}_3.$ The parent ${\mathrm{CaMnO}}_3$ is an antiferromagnetic band insulator, and shows an insulator-metal crossover with electron doping, together with an enhanced ferromagnetic component. We have found an enhancement of the specific heat jump $\Delta C$ at the spin-ordering temperature $T_{\mathrm{spin}}$ and interpreted the enhancement in terms of the intrinsic charge separation.

• Received 5 June 2001

DOI:https://doi.org/10.1103/PhysRevB.64.214409