Mn55 NMR study of the electron-doped manganite Bi0.125 Ca0.875 Mn O3

We have carried out Mn55 NMR measurements on Bi0.125 Ca0.875 Mn O3 and CaMn O3. NMR signals have been observed for Bi0.125 Ca0.875 Mn O3 at 4.2 K around 100 MHz, 320 MHz, and 605 MHz. The lines around 100 MHz and 605 MHz are ascribed to regions with ferromagnetic spin structure from their behavior in external magnetic fields. The main resonance line observed around 320 MHz has two peaks at 298 and 318 MHz at 4.2 K. The magnetic field dependence of the lines up to 4 T show that they originate from regions with antiferromagnetic spin structure. This is consistent with the observed lack of saturation of the magnetization at high magetic fields.