The results of polarized Raman scattering, far-infrared (FIR) absorption, Kramers-Kronig analysis of FIR reflectance, and lattice-dynamical calculations of the perovskitelike compound ${\mathrm{YBaCuFeO}}_5$ (space group P4mm) are reported. All 16 Raman- and infrared-active Γ-point phonons (6${\mathit{A}}_1$+2${\mathit{B}}_1$+8E) have been identified and assigned to definite atomic vibrations in close comparison with the structurally similar tetragonal ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_6$ system. The appearance of an additional strong Raman line at 576 ${\mathrm{cm}}^{\mathrm{-}1}$ is discussed in terms of disorder-induced Raman scattering. The normal-mode frequencies are in reasonable agreement with the results of lattice-dynamical calculations in the framework of a shell model with parameters extracted from several metallic oxides and perovskite compounds.

• Received 29 December 1992

DOI:https://doi.org/10.1103/PhysRevB.47.15201