Low‐Temperature Single‐Crystal Structure and Phonon Properties of A‐Site Ordered Double Perovskite CaMnTi₂O₆

Abstract

We have used high‐pressure methods to synthesize CaMnTi2O6 single crystals with edge lengths of up to 70 μm. Compared to previously reported synthetic pathways, we were able to use gold capsules and smaller pressures of 4 GPa. X‐ray diffraction analysis of the single crystals at low temperatures between 100 and 230 K confirmed that no phase transitions occur in this temperature range. We found square planar‐coordinated Mn ions to shift further out of the plane with lower temperatures which could lead to a higher polarization. The measured Raman spectrum of CaMnTi2O6 has been compared with quantum chemically calculated Raman spectrum to assign the vibrational modes. Calculated single‐crystal Raman spectrum has also been also analyzed from the point of view of direction dependency of the Raman intensities.