The low-temperature ferromagnetic insulator (FMI) phase of La1-xSrxMnO3 (x = 0.11.0.12) was investigated by convergent-beam electron diffraction (CBED) together with selected-area electron diffraction (SAED). We have revealed that the FMI phase belongs to the triclinic space group P1̄, and has a unit cell of ∼2ac x 46c x 4cc, where ac, bc, cc are lattice parameters in the pseudocubic perovskite notation. These findings indicate that the FMI phase is neither the re-entrant phase of the high temperature phase (∼√2ac x 2√2bc x 2cc) as reported by Kawano et al. nor the polaron-ordering phase with a unit cell of (∼2ac x 2bc x 4cc) as proposed by Yamada et al.
- Convergent-beam electron diffraction
- Perovskite manganite
- Space group determination
- Structural phase transformation