Structural Aspects of the Metal-Insulator Transitions in Cr-Doped V $O_{2}$

1 April 1972

journal article
research article
Published by American Physical Society (APS) in Physical Review B

Vol. 5 (7), 2541-2551
https://doi.org/10.1103/physrevb.5.2541

Abstract

The temperature-composition phase diagram of

V_{1 - x} {Cr}_{x} O_{2}

with

0 \leq x \leq 0. 025

is found to contain four phases: rutile (

R

), normal monoclinic V

O_{2}

(

M_{1}

), and two monoclinic phases (

M_{2}

and

M_{3}

). For

M_{2}

with

x = 0. 024

at 298 °K,

2 a_{R} \approx a_{M} = 9. 0664

2 c_{R} \approx b_{M} = 5. 7970

a_{R} \approx c_{M} = 4. 5255

Å, and

β = {91. 88}^{\circ}

. The

M_{2}

and

M_{3}

regions are separated by a volume discontinuity. There are two types of V atoms in these structures. The first type form pairs and the second type form zig-zag chains along the

b_{M}

axis. This contrasts with V

O_{2}

where all the vanadium atoms are paired. The structures

R

M_{2}

, and

M_{3}

with

x = 0. 024

have been refined from single-crystal x-ray data. High-pressure resistivity and x-ray measurements vs temperature give

\frac{d T (M_{2} \to R)}{dP} = - (0. 9 \pm 0. 1)

°K/kbar and

V_{R} - V_{M_{2}} = 0. 11

{cm}^{3}

/mole V

O_{2}

. At higher pressures

\frac{d T (M_{3} \to R)}{dP} = (0 \pm 0. 2)

°K/kbar. These results cannot be simply interpreted in terms of the homopolar bond model proposed for the

M_{1}

phase of V

Keywords

This publication has 19 references indexed in Scilit:

Electronic Specific Heat of Metallic Ti-Doped $V_{2}$ $O_{3}$
Physical Review Letters, 1971
Proprietes physiques et structurales de la phase CrxV1−xO2
Materials Research Bulletin, 1971
X-ray diffraction studies of the metal insulator transitions in Ti4O7, V4O7 and VO2
Materials Research Bulletin, 1970
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Materials Research Bulletin, 1970
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Materials Research Bulletin, 1970
Mott Transition in Cr-Doped $V_{2}$ $O_{3}$
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Cited by 366 articles

Structural Aspects of the Metal-Insulator Transitions in Cr-Doped VO2

Abstract

Keywords

Structural Aspects of the Metal-Insulator Transitions in Cr-Doped V $O_{2}$