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MSM X-ray Facility


Lattice parameters for measuring phase transitions

D. Pesquera et al., Nature Communications 11, 3190 (2020).

Reciprocal space maps measured using P2 show that the electrically induced switching of electric polarization in Lead Magnesium Niobate-Lead Titanate (PMN-PT) and macroscopic strain are associated with the interconversion of of orthorhombic (O) and rhombohedral (R) phases. Reciprocal space maps are made for the pseudocubic (222) and (031) planes, whose asymmetric reflections undergo complementary splitting due to the presence of domains.

Electrically driven phase transition in PMN-PT. (a-c) For major loops of electric field E, we show (a) polarization P (grey) deduced from switching current I (orange), and in-plane strains (b) εx and (c) εy. Coloured points identify coloured kV cm-1 values of E in (d,e), where we show reciprocal space maps around the (d) 222pc and (e) 031pc reflections obtained first at zero-field after a rejuvenating anneal in air at 150 °C, then at zero-field after negative poling, and then at increasing values of E. Intensity scale runs from purple (low) to red (high). Scattering vector q = (2/λ)sin(θ) for Bragg angle θ. Data in (a-c) acquired simultaneously using PMN-PT from the same master as sample A. Data in (a-e) for Sample A. (f) Pseudocubic unit cell showing the (011)pc surface (two bold black lines) and the (222)pc and (031)pc lattice planes. (e-j) For the R-phase (orange) and O-phase (purple), schematics of the reciprocal space maps show the (g) 222pc and (h) 031pc reflections, which are split (solid outlines) or unsplit (dashed outlines) according to whether (i,j) the projections of the unit cell over the corresponding real-space planes present twinning (solid outlines) or not (dashed outlines). Red arrows in (i,j) denote permitted directions of polarization.


Lattice parameters for general information


Lattice paramters for chemical composition


Lattice parameters for strain


Lattice parameters for strain and chemical composition