TY - JOUR

T1 - Preparation, structure, and charge transport characteristics of BIFEVOX ultrafine powders

AU - Buyanova, E. S.

AU - Petrova, S. A.

AU - Emel’yanova, Yu. V.

AU - Blinova, A. L.

AU - Morozova, M. V.

AU - Zhukovskii, V. M.

AU - Zhuravlev, V. D.

N1 - This work was supported by the Russian Foundation for Basic Research (project nos. 06-03-32378, 07-03-00446).

PY - 2009/8/1

Y1 - 2009/8/1

N2 - Existence boundaries, structure, and transport parameters of ultrafine powders were studied in Bi4V2 - x Fe (x) O11 - x (BIFEVOX) solid solutions. The details of synthesis of the solid solutions via liquid precursors are analyzed comparatively. In general, BIFEVOX formation via liquid precursors is similar to phase formation in solid-phase synthesis. With low iron levels (x = 0.05-0.1), solid solutions are formed in the monoclinic alpha phase (space group C2/m) The compositions with x = 0.125 and 0.15 are mixtures of alpha- and beta phases. In the range 0.2 < x < 0.7, the Bi4V2 - x Fe (x) O11 - x solid solution has the structure of the gamma phase of Bi4V2O11 (space group I4/mmm). The beta phase in the system in question has a very narrow existence range in the vicinity of x = 0.175. The average particle sizes of the powders prepared by various methods are within 0.5-3 mu m. In the powders prepared via liquid precursors, however, the distribution peak shifts toward smaller sizes, to 0.3-1 mu m. Mechanical activation conserves the structure of the gamma phase of BIFEVOX, and unit cell parameters change only insignificantly; however, the crystal lattice is slightly distorted. The electrical conductivity of BIFEVOX was studied as a function of temperature, preparation technology, and composition using impedance spectroscopy. Equivalent circuits of cells were analyzed. The conductivity of samples prepared by solution technology is always higher than for samples prepared by the solid-phase process. Features of electrical conductivity versus temperature for various phases are noted. All transitions on the conductivity curves match the features of linear thermal expansion curves. Compositions with doping levels x= 0.1-0.3 have the highest total conductivities.

AB - Existence boundaries, structure, and transport parameters of ultrafine powders were studied in Bi4V2 - x Fe (x) O11 - x (BIFEVOX) solid solutions. The details of synthesis of the solid solutions via liquid precursors are analyzed comparatively. In general, BIFEVOX formation via liquid precursors is similar to phase formation in solid-phase synthesis. With low iron levels (x = 0.05-0.1), solid solutions are formed in the monoclinic alpha phase (space group C2/m) The compositions with x = 0.125 and 0.15 are mixtures of alpha- and beta phases. In the range 0.2 < x < 0.7, the Bi4V2 - x Fe (x) O11 - x solid solution has the structure of the gamma phase of Bi4V2O11 (space group I4/mmm). The beta phase in the system in question has a very narrow existence range in the vicinity of x = 0.175. The average particle sizes of the powders prepared by various methods are within 0.5-3 mu m. In the powders prepared via liquid precursors, however, the distribution peak shifts toward smaller sizes, to 0.3-1 mu m. Mechanical activation conserves the structure of the gamma phase of BIFEVOX, and unit cell parameters change only insignificantly; however, the crystal lattice is slightly distorted. The electrical conductivity of BIFEVOX was studied as a function of temperature, preparation technology, and composition using impedance spectroscopy. Equivalent circuits of cells were analyzed. The conductivity of samples prepared by solution technology is always higher than for samples prepared by the solid-phase process. Features of electrical conductivity versus temperature for various phases are noted. All transitions on the conductivity curves match the features of linear thermal expansion curves. Compositions with doping levels x= 0.1-0.3 have the highest total conductivities.

UR - https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=tsmetrics&SrcApp=tsm_test&DestApp=WOS_CPL&DestLinkType=FullRecord&KeyUT=000268881300005

UR - http://www.scopus.com/inward/record.url?partnerID=8YFLogxK&scp=68949168789

U2 - 10.1134/S0036023609080051

DO - 10.1134/S0036023609080051

M3 - Article

VL - 54

SP - 1193

EP - 1204

JO - Russian Journal of Inorganic Chemistry

JF - Russian Journal of Inorganic Chemistry

SN - 0036-0236

IS - 8

ER -