skip to main content

SciTech ConnectSciTech Connect

Title: Accurate crystal-structure refinement of Ca{sub 3}Ga{sub 2}Ge{sub 4}O{sub 14} at 295 and 100 K and analysis of the disorder in the atomic positions

The accurate X-ray diffraction study of a Ca{sub 3}Ga{sub 2}Ge{sub 4}O{sub 14} crystal (sp. gr. P321, Z = 1) has been performed using repeated X-ray diffraction data sets collected on a diffractometer equipped with a CCD area detector at 295 and 100 K. The asymmetric disorder in the atomic positions in Ca{sub 3}Ga{sub 2}Ge{sub 4}O{sub 14} is described in two alternative ways: with the use of anharmonic atomic displacements (at 295 K R/wR = 0.68/0.60%, 3754 reflections; at 100 K R/wR = 0.90/0.70%, 3632 reflections) and using a split model (SM) (at 295 K R/wR = 0.74/0.67%; at 100 K R/wR = 0.95/0.74%). An analysis of the probability density function that defines the probability of finding an atom at a particular point in space shows that, at 295 K, five of the seven independent atoms in the unit cell are asymmetrically disordered in the vicinity of their sites, whereas only three atoms are disordered at 100 K. At both temperatures the largest disorder is observed at the 3f site on a twofold axis, which is a prerequisite for the formation of helicoidal chains of atoms along the c axis of the crystal and can serve as a structural basis formore » multiferroic properties of this family of crystals with magnetic ions.« less
Authors:
 [1] ;  [2]
  1. Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)
  2. Moscow State University (Russian Federation)
Publication Date:
OSTI Identifier:
22121690
Resource Type:
Journal Article
Resource Relation:
Journal Name: Crystallography Reports; Journal Volume: 58; Journal Issue: 4; Other Information: Copyright (c) 2013 Pleiades Publishing, Ltd.; http://www.springer-ny.com; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ASYMMETRY; ATOMIC DISPLACEMENTS; CRYSTALS; PROBABILITY; PROBABILITY DENSITY FUNCTIONS; REFLECTION; TEMPERATURE RANGE 0273-0400 K; TRIGONAL LATTICES; X-RAY DIFFRACTION