Order-disorder vs Displacive structural phase transitions in (Ca<sub>x</sub>Sr<sub>1-x</sub>)<sub>3</sub>Rh<sub>4</sub>Sn<sub>13</sub>
ORAL
Abstract
A three-dimensional quasi-skutterudite compound (CaxSr1-x)3Rh4Sn13 undergoes a second-order structural phase transitions from a simple cubic I phase structure (Pm-3n) to a body-centered cubic I’ superstructure (I-43d) but the nature of transition either displacive or order-disorder has not been categorized yet. To distinguish between these two characters, local order parameter fluctuations were estimated by transforming the x-ray diffuse scattering data of single crystal (CaxSr1-x)3Rh4Sn13 with x=0.0, 0.1, 0.6, 0.65, 0.7, 0.9 to a real space producing a three-dimensional pair distribution function using a new ‘Gaussian tiling’ approach rather than a conventional ‘punch and fill’ method. The 3D-ΔPDF analysis shows that the amplitudes of local atomic displacements are independent of both temperature and doping, a much clearer signature of order-disorder transitions than possible by other methods.
This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.
This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.
*This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.
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Presenters
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Puspa Upreti
- Department of Physics, Northern Illinois University, Materials Science Division, Argonne National Laboratory