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Twin structure of LSGMO crystals studied by Laue method

Dmytro I. Savytskii 2Dmytro M. Trots 2A. Matkovskii 2Carsten Paulmann 1Ulrich Bismayer 1Marek Berkowski 3

1. University of Hamburg, Mineralogisch-Pertographisches Institut, Hamburg, Germany
2. Lviv Polytechnic National University, 12 Bandera, Lviv 79013, Ukraine
3. Polish Academy of Sciences, Institute of Physics, al. Lotników 32/46, Warszawa 02-668, Poland

Abstract

Twin domains and their boundaries are the dominant microstructural features in many perovskites. Increasing interest in perovskite-like compounds for advanced energy applications has led to intensive research on real structures since it substantially influence the physical properties. The "white" character of synchrotron radiation re-actualized the old Laue method: it is now possible to record thousands of diffraction spots from very small crystals in a very short time using a charge-coupled device (CCD) area detector.
An investigation of real structure in La0.95Sr0.05Ga0.9Mg0.1O2.92 (LSGMO) perovskite-type crystals has been undertaken using the technique of white beam X-ray diffraction in 300-1000 K temperature range. Experiments have been carried out using the Kappa-diffractometer at HASYLAB beamline F1 equipped with a SMART CCD system. La0.95Sr0.05Ga0.9Mg0.1O2.92 twinned crystals were grown using the Czochralski technique.
Characteristic twin structure is formed by the intersection of walls (010)p and (01-1)p in orthorhombic phase at room temperature. The same domain walls were observed in high temperature trigonal phase. Temperature cycling via the phase transition demonstrated that the domain structure is reversible in small crystal and is composed entirely of mutually permissible twin walls, and thus allows a stress-free intergrowth of all observed domain states in both phases. The Laue technique gave the orientation of observed domains and provided important information for the study of anisotropy of observed diffuse scattering and short vacancy ordering in oxygen conductor (La,Sr)(Ga,Mg)O3-x.

 

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Related papers

Presentation: poster at E-MRS Fall Meeting 2003, Symposium B, by Dmytro I. Savytskii
See On-line Journal of E-MRS Fall Meeting 2003

Submitted: 2003-05-06 12:08
Revised:   2009-06-08 12:55