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oai:recercat.cat:2445/106372025-12-05T00:50:54Zcom_2072_1057col_2072_478917col_2072_478923col_2072_478933

X-ray diffraction, thermal analysis, and Raman scattering study of K2BeF4 and comparation to other member of the (beta)-K2SO4 family with ferroelectric -paraelectric transition Solans, Xavier, 1949-2007 González-Silgo, Cristina Calvet Pallàs, Maria Teresa Ruiz-Pérez, C. Martínez Sarrión, María Luisa Mestres i Vila, Ma. Lourdes Difracció Ferroelectricitat Dielèctrics Diffraction Ferroelectricity Dielectrics Thermal analysis, powder diffraction, and Raman scattering as a function of the temperature were carried out on K2BeF4. Moreover, the crystal structure was determined at 293 K from powder diffraction. The compound shows a transition from Pna21 to Pnam space group at 921 K with a transition enthalpy of 5 kJ/mol. The transition is assumed to be first order because the compound shows metastability. Structurally and spectroscopically the transition is similar to those observed in (NH4)2SO4, which suggests that the low-temperature phase is ferroelectric. In order to confirm it, the spontaneous polarization has been computed using an ionic model. 2009-12-29T11:01:23Z 2009-12-29T11:01:23Z 1998 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Reproducció digital del document publicat en format paper, proporcionada per PROLA i http://dx.doi.org/10.1103/PhysRevB.57.5122 Physical Review B, 1998, vol. 57, núm. 9, p. 5122-5125 http://dx.doi.org/10.1103/PhysRevB.57.5122 (c) The American Physical Society, 1998 info:eu-repo/semantics/openAccess The American Physical Society Articles publicats en revistes (Mineralogia, Petrologia i Geologia Aplicada)