TY  - JOUR
AU  - Murphy, Gabriel L.
AU  - Kennedy, Brendan J.
AU  - Zhang, Zhaoming
AU  - Avdeev, Maxim
AU  - Brand, Helen E. A.
AU  - Kegler, Philip
AU  - Alekseev, Evgeny
TI  - Structure and phase transition in BaThO 3 : A combined neutron and synchrotron X-ray diffraction study
JO  - Journal of alloys and compounds
VL  - 727
SN  - 0925-8388
CY  - Lausanne
PB  - Elsevier
M1  - FZJ-2017-06105
SP  - 1044-1049
PY  - 2017
AB  - The structure of BaThO3, obtained by solid state synthesis, was refined for the first time by the Rietveld method using a combination of synchrotron X-ray and neutron powder diffraction data. BaThO3 has an orthorhombic structure at room temperature, in space group Pbnm with a = 6.3491(5), b = 6.3796(4) and c = 8.9907(7) Å. Heating BaThO3 to above 700 °C results in a continuous transition to a second orthorhombic structure, in space group Ibmm, demonstrated by both in situ neutron and synchrotron X-ray powder diffraction measurements. The coefficient of volumetric thermal expansion for BaThO3 is determined to be 1.04 × 10−5 °C-1 from 50 to 625 °C (Pbnm phase), and 9.43 × 10−6 °C-1 from 800 to 1000 °C (Ibmm phase). BaThO3 was found to decompose upon exposure to atmospheric moisture resulting in the formation of ThO2. The thermal expansion of ThO2, which invariably co-exists with BaThO3, is also described.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000412712900124
DO  - DOI:10.1016/j.jallcom.2017.08.200
UR  - https://juser.fz-juelich.de/record/837116
ER  -