skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Investigation of the structure and properties of quartz in the {alpha}-{beta} transition range by neutron diffraction and mechanical spectroscopy

Abstract

The paper reports on the results of complex investigations into the physical properties of synthetic quartz single crystals and quartz powders in the temperature range of the {alpha}-{beta} transition with the use of neutron diffraction and mechanical spectroscopy. The crystal structure of quartz powders with different average sizes of grains is determined in the temperature range up to 620 deg. C and in the {alpha}-{beta} transition temperature range. The temperature dependences of the internal friction and the resonant frequency for quartz samples in the vicinity of the phase transition temperature are obtained upon excitation of vibrations in the planes parallel and perpendicular to the Z axis of the quartz crystal. The temperatures at the maxima of the internal friction in the range 560-620 deg. C are determined. The assumptions regarding the possible reasons for the shift of the phase transition temperature are made. It is revealed that the internal friction is characterized by a maximum that is observed in the vicinity of 350 deg. C and is not related to the structural transformations in quartz.

Authors:
 [1];  [2]; ;  [3];  [2]
  1. Joint Institute for Nuclear Research (Russian Federation), E-mail: nikitin@nf.jinr.ru
  2. Tula State University (Russian Federation)
  3. Joint Institute for Nuclear Research (Russian Federation)
Publication Date:
OSTI Identifier:
21090921
Resource Type:
Journal Article
Resource Relation:
Journal Name: Crystallography Reports; Journal Volume: 52; Journal Issue: 3; Other Information: DOI: 10.1134/S1063774507030145; Copyright (c) 2007 Nauka/Interperiodica; Article Copyright (c) 2007 Pleiades Publishing, Inc; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CRYSTAL STRUCTURE; INTERNAL FRICTION; MONOCRYSTALS; NEUTRON DIFFRACTION; PHASE TRANSFORMATIONS; QUARTZ; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0400-1000 K; TRANSITION TEMPERATURE

Citation Formats

Nikitin, A. N., Markova, G. V., Balagurov, A. M., Vasin, R. N., and Alekseeva, O. V. Investigation of the structure and properties of quartz in the {alpha}-{beta} transition range by neutron diffraction and mechanical spectroscopy. United States: N. p., 2007. Web. doi:10.1134/S1063774507030145.
Nikitin, A. N., Markova, G. V., Balagurov, A. M., Vasin, R. N., & Alekseeva, O. V. Investigation of the structure and properties of quartz in the {alpha}-{beta} transition range by neutron diffraction and mechanical spectroscopy. United States. doi:10.1134/S1063774507030145.
Nikitin, A. N., Markova, G. V., Balagurov, A. M., Vasin, R. N., and Alekseeva, O. V. Tue . "Investigation of the structure and properties of quartz in the {alpha}-{beta} transition range by neutron diffraction and mechanical spectroscopy". United States. doi:10.1134/S1063774507030145.
@article{osti_21090921,
title = {Investigation of the structure and properties of quartz in the {alpha}-{beta} transition range by neutron diffraction and mechanical spectroscopy},
author = {Nikitin, A. N. and Markova, G. V. and Balagurov, A. M. and Vasin, R. N. and Alekseeva, O. V.},
abstractNote = {The paper reports on the results of complex investigations into the physical properties of synthetic quartz single crystals and quartz powders in the temperature range of the {alpha}-{beta} transition with the use of neutron diffraction and mechanical spectroscopy. The crystal structure of quartz powders with different average sizes of grains is determined in the temperature range up to 620 deg. C and in the {alpha}-{beta} transition temperature range. The temperature dependences of the internal friction and the resonant frequency for quartz samples in the vicinity of the phase transition temperature are obtained upon excitation of vibrations in the planes parallel and perpendicular to the Z axis of the quartz crystal. The temperatures at the maxima of the internal friction in the range 560-620 deg. C are determined. The assumptions regarding the possible reasons for the shift of the phase transition temperature are made. It is revealed that the internal friction is characterized by a maximum that is observed in the vicinity of 350 deg. C and is not related to the structural transformations in quartz.},
doi = {10.1134/S1063774507030145},
journal = {Crystallography Reports},
number = 3,
volume = 52,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • {beta}-BaAlF{sub 5} is monoclinic (space group P2{sub 1}/n): a = 5.1517(1) {angstrom}, b = 19.5666(4) {angstrom}, c = 7.5567(2) {angstrom}, {beta} = 92.426(1){degree}, Z = 8. {gamma}-BaAlF{sub 5} is monoclinic (space group P2{sub 1}): a = 5.2584(1) {angstrom}, b = 9.7298(2) {angstrom}, c = 7.3701(2) {angstrom}, {beta} = 90.875(1){degree}, Z = 4. Both structures are determined ab initio from X-ray powder data; final results are given from neutron powder data refinements (R{sub I} = 0.038, R{sub P} = 0.072, and R{sub WP} = 0.087 and R{sub I} = 0.048, R{sub P} = 0.083, and R{sub WP} = 0.101 for themore » {beta} and {gamma} phases, respectively). Like {alpha}-BaAlF{sub 5}, the {beta} and {gamma} phases are built up from isolated infinite (AlF{sub 5}){sup 2n{minus}}{sub n} chains with AlF{sub 6} octahedra sharing corners in a cis-position. Close structural relationships are shown to exist between the Ba-Al cationic subnetwork of: {alpha}-BaAlF{sub 5} and the CrB-type structure; {beta}-BaAlF{sub 5} and the SrAg-type; {gamma}-BaAlF{sub 5} and the FeB-type.« less
  • Abstract not provided.
  • A high-precision single-crystal neutron diffraction determination of the crystal and molecular structure of (eta/sup 5/-C/sub 5/H/sub 5/)/sub 2/MoH/sub 2/ has been carried out in order to resolve previous x-ray and neutron diffraction studies which produced structural models which are inconsistent with modern bonding theories. The complex crystallizes in space group C2/c with cell parameters of a = 14.311 (7) A, b = 5.905 (3) A, c = 10.440 (5) A, ..beta.. = 104.15 (2)/sup 0/, and Z = 4. Intensity data were measured for two independent octants out to (sin theta)/lambda = 0.72. The structure was solved by direct methodsmore » and refinement led to final discrepancy indices of R(F/sub 0//sup 2/) = 0.074 and R/sub w/(F/sub 0//sup 2/) = 0.101. The dihedral angle between the two cyclopentadienyl planes is 34.2/sup 0/, and the C--C bond lengths within each ring are indicative of a completely delocalized ..pi.. system. The coordinates of the metal-bonded hydrogen atom have been unequivocally located and refined, and a Mo--H distance of 1.685 (3) A and a H--Mo--H' angle of 75.5 (3)/sup 0/ has been obtained. The new structural parameters determined for (eta/sup 5/-C/sub 5/H/sub 5/)/sub 2/MoH/sub 2/ are substantially different from those previously reported but are in excellent agreement with those predicted today for transition metal cyclopentadienyl hydrides.« less
  • Bi{sub 0.8}A{sub 0.2}FeO{sub 3} (A = La, Ca, Sr, Ba) multiferroics were studied using x-ray, neutron diffraction and magnetization techniques. All the samples crystallized in rhombohedral structure with space group R3c. The compounds exhibit antiferromagnetic (AFM) ordering at 300 K and no evidence of further structural or magnetic transition was observed on lowering of temperature below it. The magnetic structure of these substituted compounds are found to be collinear G-type AFM structure as against the non collinear incommensurate magnetic structure reported in the case of parent compound. The moments on Fe at 6 K are aligned along the a-axis inmore » the case of Ca-doped sample. With increase in the ionic radii of dopant, the moments are found to be aligned in the ac plane and the angle of tilt away from the a-axis increases. The observed change in the magnetic structure with substitution is attributed to the intrinsic structural distortion as evidenced by the change in the bond angle (Fe-O-Fe) and bond distances (Bi-O, Fe-O). It has been found that heterovalent substitution A{sup 2+} results in the formation of oxygen vacancies in the parent lattices as the possibility of Fe{sup 4+} ruled out by M√∂ssbauer spectra recorded at room temperature. Higher value of remnant magnetization (0.4187 emu/g) and coercivity (4.7554kOe) is observed in Bi{sub 0.8}Ba{sub 0.2}FeO{sub 3} sample in comparison to other substituted samples revealing a strong correlation between ionic radii and magnetization.« less