摘要
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 123K. The temperature variation phonon mode at 685cm^-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 TN of the film than that of the bulk counterpart is also discussed.
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 123K. The temperature variation phonon mode at 685cm^-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 TN of the film than that of the bulk counterpart is also discussed.
基金
Supported by the National Natural Science Foundation of China under Grant No 50802023, the Scientific and Technological Brainstorm Key Project of Henan Province （082102270039, 102102210115）, the Finance Assistance Scheme of Backbone Youth Teachers in University of Henan Province （2009GGJS-026）, Research Plan for Natural Science in the Education Department of Henan Province （2008B140003, 2009A430002）, and the Research Fund of Henan University （07YBGGO08）.
