Coherent intergrowth of simple cubic and quintuple tetragonal perovskites in the system Nd2−εBa3+ε(Fe,Co)5O15−δ

Investigation of the Nd2−εBa3+ε(Fe,Co)5O15−δ system, combining X-ray diffraction and electron microscopy, has allowed a tetragonal quintuple ordered perovskite “ap×ap×5ap” phasoid inter-grown within a single cubic perovskite matrix to be evidenced for ε=0. This nanoscale chemically twinned perovskite is compared with other members, Ln=Sm, Eu, Pr. The unusual long range ordering of the layers develops strains due to size mismatch between Ba2+ and Ln3+ cations. Importantly, two factors allow the strains to be decreased: (i) special intergrowths of double (LnBaFe2O6−δ) and triple (LnBa2Fe3O9−δ) perovskite ribbons/layers oriented at 90°, (ii) nanoscale chemical twinning. The spin locking effect of the nano-domain boundaries upon the magnetic properties of these perovskites is discussed.

Nd2Ba3Fe5O14.54 is a tetragonal quintuple perovskite phasoid embedded in a simple cubic perovskite matrix, which shows collinear antiferromagnetic behavior.Figure optionsDownload as PowerPoint slide