Temperature-Dependent Raman Spectrum of Hexagonal YMnO₃ Films Synthesized by Chemical Solution Method

We study the temperature-dependent Raman spectrum of hexagonal YMnO₃ films prepared by a chemical solution method. There are seven Raman peaks (3A₁+E₁+4E₂) of the film identified at room temperature. From the results of temperature dependence of the Raman spectrum, it is deduced that the YMnO₃ film has a magnetic phase transition temperature of about 123 K. The temperature variation phonon mode at 685 cm^-1 shows an anomalous frequency variation near 123 K, suggesting either a more complex mechanism of spin-phonon coupling or strong mixing of phonon modes. The reason for the higher antiferromagnetic Néel temperature T_N of the film than that of the bulk counterpart is also discussed.