10.1021/acs.inorgchem.7b00345.s002
Gabriella Giampaoli
Gabriella
Giampaoli
Jun Li
Jun
Li
Arthur P. Ramirez
Arthur P.
Ramirez
Arthur W. Sleight
Arthur W.
Sleight
M. A. Subramanian
M. A.
Subramanian
Bi<sub>2–<i>x</i></sub>Ca<sub><i>x</i></sub>Ir<sub>2</sub>O<sub>6+<i>y</i></sub> Pyrochlore
Phases: Structure and Properties with Varied Ir Oxidation State from 3.9+ to 4.3+
American Chemical Society
2017
resistivity
site
756 K
Ir oxidation state
Seebeck coefficient
Bi
Varied Ir Oxidation State
Pyrochlore
neutron diffraction data
2017-04-05 13:54:01
Dataset
https://acs.figshare.com/articles/dataset/Bi_sub_2_i_x_i_sub_Ca_sub_i_x_i_sub_Ir_sub_2_sub_O_sub_6_i_y_i_sub_Pyrochlore_Phases_Structure_and_Properties_with_Varied_Ir_Oxidation_State_from_3_9_to_4_3_/4818484
Pyrochlore phases Bi<sub>2–<i>x</i></sub>Ca<sub><i>x</i></sub>Ir<sub>2</sub>O<sub>6</sub>O<sub><i>y</i></sub><sup>′</sup> with <i>x</i> from 0.0 to
1.0 have been evaluated based on Rietveld analysis of neutron diffraction
data, electrical resistivity and thermopower data from 3 to 756 K,
and magnetic susceptibility data from 3 to 298 K. The average Ir oxidation
state is less than 4+ at low <i>x</i>, above 4+ for high <i>x</i>, and is very close to 4+ at <i>x</i> = 0.5.
All samples show metallic properties with an electrical resistivity
of ∼10<sup>–3</sup> Ω·cm at room temperature.
For low <i>x</i>, the sign of the Seebeck coefficient is
negative at low temperature but becomes positive at high temperature.
For high <i>x</i>, the sign of the Seebeck coefficient is
positive from 3 to 756 K. Magnetic measurements indicate no magnetic
ordering down to 3 K for all values of <i>x</i>. All Bi
is in its ideal position for all values of <i>x</i>, but
much of the Ca is strongly displaced from the ideal A cation site.
This displacement of Ca apparently only occurs when there is an adjacent
vacancy at the O′ site.