10.1021/acs.cgd.5b00525.s002
Ignacio
Blazquez Alcover
Ignacio
Blazquez
Alcover
Rénald David
Rénald
David
Sylvie Daviero-Minaud
Sylvie
Daviero-Minaud
Dmitry Filimonov
Dmitry
Filimonov
Marielle Huvé
Marielle
Huvé
Pascal Roussel
Pascal
Roussel
Houria Kabbour
Houria
Kabbour
Olivier Mentré
Olivier
Mentré
Reversible Exsolution
of Nanometric Fe<sub>2</sub>O<sub>3</sub> Particles in BaFe<sub>2–<i>x</i></sub>(PO<sub>4</sub>)<sub>2</sub> (0 ≤ <i>x</i> ≤
2/3): The Logic of Vacancy Ordering in Novel Metal-Depleted Two-Dimensional
Lattices
American Chemical Society
2015
members x
Fe ions
2 D ferrimagnets
Reversible Exsolution
x values
honeycomb layers
2 D ferromagnets
Vacancy Ordering
Nanometric Fe 2O Particles
crystal chemistry
50 nm diameter
iron oxide
grain surface
2015-09-02 00:00:00
Dataset
https://acs.figshare.com/articles/dataset/Reversible_Exsolution_of_Nanometric_Fe_sub_2_sub_O_sub_3_sub_Particles_in_BaFe_sub_2_i_x_i_sub_PO_sub_4_sub_sub_2_sub_0_i_x_i_2_3_The_Logic_of_Vacancy_Ordering_in_Novel_Metal_Depleted_Two_Dimensional_Lattices/2135875
We show here that the exsolution
of Fe<sup>2+</sup> ions out of
two-dimensional (2D) honeycomb layers of BaFe<sub>2</sub>(PO<sub>4</sub>)<sub>2</sub> into iron-deficient BaFe<sub>2–<i>x</i></sub>(PO<sub>4</sub>)<sub>2</sub> phases and nanometric α-Fe<sub>2</sub>O<sub>3</sub> (typically 50 nm diameter at the grain surface)
is efficient and reversible until <i>x</i> = 2/3 in mild
oxidizing/reducing conditions. It corresponds to the renewable conversion
of 12 wt % of the initial mass into iron oxide. After analyzing single
crystal X-ray diffraction data of intermediate members <i>x</i> = 2/7, <i>x</i> = 1/3, <i>x</i> = 1/2 and the
ultimate Fe-depleted <i>x</i> = 2/3 term, we observed a
systematic full ordering between Fe ions and vacancies (V<sub>Fe</sub>) that denote unprecedented easy in-plane metal diffusion driven
by the Fe<sup>2+</sup>/Fe<sup>3+</sup> redox. Besides the discovery
of a diversity of original depleted triangular <sub>∞</sub>{Fe<sup>2/3+</sup><sub>2–<i>x</i></sub>O<sub>6</sub>} topologies, we propose a unified model correlating the <i>x</i> Fe-removal and the experimental Fe/V<sub>Fe</sub> ordering
into periodic one-dimensional motifs paving the layers, gaining insights
into predictive crystal chemistry of complex low dimensional oxides.
Increasing the <i>x</i> values led to a progressive change
of the materials from 2D ferromagnets (Fe<sup>2+</sup>) to 2D ferrimagnets
(Fe<sup>2/3+</sup>) to antiferromagnets for <i>x</i> = 2/3
(Fe<sup>3+</sup>).