Thermal expansion, compressibility and bulk modulus of ilmenite-type CoTiO3: X-ray diffraction at high pressures and temperatures

Autor(es)

Cunha, T. R. ^[1] ; Rodrigues, A. D. ^[1] ; Rodrigues, J. E. ^[1] ; Sampaio, V, D. ; Moulton, B. J. A. ^[2] ; da Costa, R. C. ^[3] ; Pizani, P. S. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Dept Phys, BR-13565905 Sao Carlos - Brazil

^[2] Sampaio, D., V, Univ Fed Sao Carlos, Dept Phys, BR-13565905 Sao Carlos - Brazil

^[3] Univ Fed Campina Grande, Dept Environm Engn, BR-58840000 Pombal - Brazil

• Tipo de documento: Artigo Científico
• Fonte: SOLID STATE SCIENCES; v. 88, p. 1-5, FEB 2019.
• Citações Web of Science: 0

Resumo

In this paper we report about the in-situ experiments on cobalt titanate (CoTiO3), in which were investigated the compressibility at high pressures up to 24.6 GPa, at room temperature, using synchrotron X-ray diffraction (SXRD) and also the thermal expansion at high temperatures, from 298 to 723 K, using a conventional diffractometer at atmospheric pressure. The diffraction patterns were analyzed using the Rietveld method. The obtained lattice parameters were used to determine thermodynamic data of the CoTiO3 in its ilmenite phase: the bulk modulus, compressibility, and thermal expansion coefficients. It was observed that increasing pressure, the volume of the unit cell decreased from 306.16 angstrom(3) to 266.01 angstrom(3). The third-order Birch-Murnaghan equation of state was fitted to determine the bulk modulus, B-0, and its pressure derivative, B'(0) along with the compressibility of the a- and c-crystallographic axis. In contrast, increasing temperature caused a volumetric expansion of the unit cell from 306.16 angstrom(3) to 309.92 angstrom(3). In both cases, changes in the c-axis dominate the expansion or contraction of the unit cell. Within the pressure and temperature ranges investigated in this paper, no structural phase transition was observed. (AU)

• Processo FAPESP: 16/15962-0 - Correlação entre estrutura e propriedades dinâmicas e ópticas de materiais da série (Ax, A'1-x)O + SiO2 (A, A' = Pb, Ni, Co, Fe, Cr): estudo por espalhamento Raman e simulações por dinâmica molecular
• Beneficiário: David Vieira Sampaio
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 13/07793-6 - CEPIV - Centro de Ensino, Pesquisa e Inovação em Vidros
• Beneficiário: Edgar Dutra Zanotto
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 16/18567-5 - Ordenamento estrutural pré-nucleação em vidros que nucleiam homogeneamente: BaO-2SiO2 e CaO-SiO2
• Beneficiário: Benjamin John Albert Moulton
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado