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

Author(s)

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]

Affiliation

^[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

• Document type: Journal article
• Source: SOLID STATE SCIENCES; v. 88, p. 1-5, FEB 2019.
• Web of Science Citations: 0

Abstract

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)

• FAPESP's process: 16/15962-0 - Correlation between materials structure and dynamic and optical properties of (Ax, A'1-x)O + SiO2 (A, A' = Pb, Ni, Co, Fe, Cr) series: Raman scattering and molecular dynamics simulations
• Grantee: David Vieira Sampaio
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/07793-6 - CEPIV - Center for Teaching, Research and Innovation in Glass
• Grantee: Edgar Dutra Zanotto
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 16/18567-5 - Nuclei entrapment: the pre-nucleation structural ordering of homogeneous nucleating BaO-2SiO2 and CaO-SiO2 glasses
• Grantee: Benjamin John Albert Moulton
• Support Opportunities: Scholarships in Brazil - Post-Doctoral