Synthesis, structure and properties of heavily Mn-doped perovskite-type SrTiO3 nanoparticles

• Heavily Mn-doped perovskite SrTi1−xMnxO3 nanopowders were firstly synthesized.
• Activation of the Last TO2 mode reveals polar ordering at low temperatures.
• Appearance of the polar phase is accompanied by magnetic ordering (multiferroicity).

Cubic perovskite SrTi1−xMnxO3 nanopowders with x = 0–0.5, which is much higher than the conventionally believed Mn incorporation limit, and particles sizes 10–80 nm have been successfully synthesized using the citrate sol–gel method. The crystalline structure, the morphology, the chemical composition and the lattice constant behavior versus the annealing temperature and the Mn concentration have been characterized using X-ray diffraction, scanning electron microscopy and proton-induced X-ray emission techniques. Studies of Raman light scattering and the magnetic properties revealed the activation of the TO2 polar mode and the magnetic ordering effects at low temperatures. Such features are treated as possible evidence of non-d0 Mn-driven transition to a polar phase with multiferroicity in heavily concentrated perovskite SrTi1−xMnxO3 nanopowders.