Utilize este identificador para referenciar este registo:
https://hdl.handle.net/1822/13943
Título: | The phase transition sequence of betaine arsenate investigated by infrared reflectivity |
Autor(es): | Ribeiro, J. L. Vieira, L. G. Dekola, T. Gomes, I. Tarroso |
Palavras-chave: | Phase transitions Infrared spectroscopy Solid organic materials Ferroelectric and antiferroelectric materials Phonon–photon interaction Infrared spectra |
Data: | 2009 |
Revista: | Vibrational Spectroscopy |
Resumo(s): | The ac-polarized infrared reflectivity spectra of betaine ortho-arsenic acid single crystals have been measured throughout the ferroelastic–ferroelectric phase transition observed near Tc2 = 120 K. The monoclinic symmetry of the system was explicitly taken into account and a three-polarization technique used for the first time to investigate in detail the critical behaviour of the Bu polar phonons. The results show that near the THz frequency range, the usual approximation of considering the system as pseudoorthorhombic fails, giving rise to errors in the determination of the optical parameters. The obtained spectroscopic data indicate that the phase diagram and the physical mechanism involved in the stabilization of ferroelectricity in betaine arsenate (BA) are more complex than the prevalent view of a simple ordering process in bistable hydrogen bonds. |
Tipo: | Artigo |
URI: | https://hdl.handle.net/1822/13943 |
Arbitragem científica: | yes |
Acesso: | Acesso restrito UMinho |
Aparece nas coleções: | CDF - FCD - Artigos/Papers (with refereeing) |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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vibrational spectroscopy50_198(2009).pdf Acesso restrito! | 890,89 kB | Adobe PDF | Ver/Abrir |