Coexistence of antiferromagnetism and ferromagnetism in Ca1-xPrxMnO3 (x <=0.1) manganites

The magnetism in three polycrystalline samples of the electron doped mangan ites Ca1-xPrxMnO3 (x = 0.025, 0.051 .01) was investigated by NMR on Mn-55 a nd Pr-141 nuclei, neutron diffraction, and magnetic measurements. In all sy stems the coexistence of majority antiferromagnetic and minority ferromegne tic phases was found. At 4.2 K distinct NMR signals from ferromagnetic doma ins and antiferromagnetic matrix as well as from the domain walls were dete cted, Magnetic moment at 3.2 K increases sharply with increasing x from 0.0 6 mu(B) pfu (x = 0.025) to 0.9 mu(B) pfu (x = 0.1) accompanied by an equall y sharp increase of the ferromagnetic NMR signal. For the x = 0.1 sample th e temperature dependence of the ferromagnetic moment determined by neutrons and NMR agrees well with the magnetic measurements. For smaller x the NMR gives essentially the same dependence, while the bulk magnetization decreas es with increasing temperature more rapidly, indicating reduction of the fe rromagnetic volume when temperature is raised. For a more complete characte rization of the system studied the temperature dependencies of the electric al resistivity and thermopower were also measured.