Structures and properties of the perovskite-type compounds Na1-xSrxNbO3 
(0.1≤x≤0.9) - From insulating to metallic conductivity

Istomin, S. Y.; Svensson, G.; Köhler, J.

Item

ITEM ACTIONSEXPORT

Add to Basket

Local TagsRelease HistoryDetailsSummary

Released

Journal Article

Structures and properties of the perovskite-type compounds Na_1-xSr_xNbO₃ (0.1≤x≤0.9) - From insulating to metallic conductivity

MPS-Authors

/persons/resource/persons280161

Köhler, J.
Former Departments, Max Planck Institute for Solid State Research, Max Planck Society;
Department Nanochemistry (Bettina V. Lotsch), Max Planck Institute for Solid State Research, Max Planck Society;

External Resource

No external resources are shared

Fulltext (restricted access)

There are currently no full texts shared for your IP range.

Fulltext (public)

There are no public fulltexts stored in PuRe

Supplementary Material (public)

There is no public supplementary material available

Citation

Istomin, S. Y., Svensson, G., & Köhler, J. (2002). Structures and properties of the perovskite-type compounds Na_1-xSr_xNbO₃ (0.1≤x≤0.9) - From insulating to metallic conductivity. Journal of Solid State Chemistry, 167(1), 7-16.

Cite as: https://hdl.handle.net/21.11116/0000-000E-E4B1-8

Abstract

Reduced perovskite-type compounds with compositions Na1-
xSrxNbO3 (0.1less than or equal toxless than or equal to0.9)
have been synthesized. X-ray powder diffraction (XRD) studies
for the 0.2less than or equal toxless than or equal to0.7
phases indicate a tetragonal structure (P4/mbm) with unit-cell
parameters aapproximate toroot2 x a(per), capproximate toa(per)
(the subscript 'per' refers to the cubic perovskite structure),
and for x = 0.8 and 0.9, the space group P4/mmm was found with
aapproximate toa(per), capproximate toa(per). Structure
refinements based on XRD and neutron diffraction data using the
Rietveld technique confirmed this for Na1-xSrxNbO3, 0.3less
than or equal toxless than or equal to0.7 and x = 0.5, 0.6,
respectively. Selected-area and convergent beam electron
diffraction studies show that the crystallites of x = 0.2 and
0.3 phases in fact have the GdFeO3-type structure (space group
Pnma and unit-cell parameters aapproximate toroot2 x a(per),
bapproximate to2 x a(per), capproximate toroot2 x a(per),)
while crystallites in the 0.4less than or equal toxless than or
equal to0.9 samples consist of intergrown domains between this
orthorhombic structure and the tetragonal structure (P4/mbm).
The reason for the appearance of two phases is due to local
variations in the Na/Sr content within the crystallites.
Measurements of the magnetic susceptibilities show that the
itinerant behavior in the samples Na1-xSrxNbO3 increases with
the carrier concentration. The resistivity measurements
indicate that an insulator-metal transition takes place between
x = 0.5 and 0.6. The samples with x = 0.4 and 0.5 exhibit a
complex temperature dependence of the resistivity with a
maximum around 70 K. (C) 2002 Elsevier Science (USA).