RAMAN-SCATTERING INVESTIGATION OF THE HEXAGONAL PEROVSKITE RBZNF3

Raman spectra of the perovskite system RbZnF3 were recorded from room temperature down to 85 K, on a sample quenched in the hexagonal symmetry (normally the high-temperature phase) grown by the Czochralski technique. The results are consistent with group theory calculations done in the framework of the space group P6(3)/mmc, giving 5A(1g)+6E(1g)+8E(2g), with only 2 lines missing. A sample with cubic symmetry was also investigated between 300 and 10 K, and no additional structural phase transition was evidenced. The stability of the hexagonal structure is discussed.