Structural phase transition in a perovskite-type NH₃(CH₂)₃NH₃CuCl₄crystal – X-ray and optical studies

On the Structural Phase Transition in a Perovskite-Type Diaminopropanetetrachlorocuprate(II) NH3(CH2)3NH3CuCl4 Crystal

“…However, new domains perpendicular to existing domains appear at the transition region, and they exist in the range 2-3 K above the phase transition temperature and then they disappear. This is similar to domain appearance in monodomain samples existing in the temperature range 2-3 K above the phase transition temperature [10].…”

“…In addition, the TGA measurements did not exhibit any losses of mass on heating up to 480 K. No significant changes of the sample after heating/cooling cycles were observed by polarized microscopy. X-ray studies showed a reversible change of symmetry observed upon heating and cooling, although with a decrease of line intensity on cooling run [10]. Thus, the observed dielectric response is probably connected with the creation and rearrangement of defects above the phase transition temperature that influence electric properties (space charge) of the material above the phase transition.…”

“…3c, T = 300 K). The sample that was covered with silicone oil exhibited an unchanged yellow colour, therefore the gradual darkening of the sample is caused mainly on the surface [10].…”

“…The crystal is centrosymmetric in both phases [10] thus it excludes ferroelectricity. The room temperature space group is orthorhombic P nma but the symmetry of the phase above 433 K is monoclinic B2/m [10]. The high value of the permittivity and losses result from the huge increase of conductivity.…”

Structural characterization, thermal properties, and molecular motions near the phase transition in hybrid perovskite [(CH2)3(NH3)2]CuCl4 crystals: 1H, 13C, and 14N nuclear magnetic resonance

“…The organic chains NH 3 -CH 2 -CH 2 -CH 2 -NH 3 are almost identical, and the skeleton N-C-C-C-N is planar. Above 434 K, the symmetry is monoclinic with space group B2/m and lattice constants a = 7.309 Å, b = 8.866 Å, c = 7.614 Å, α = 95.365°, and Z = 2 22 . The lattice constants a and c in the monoclinic structure are comparable with those in the room temperature structure, whereas the b parameter in the monoclinic structure is half of that in the room temperature structure.…”