Hostname: page-component-cd9895bd7-gxg78 Total loading time: 0 Render date: 2024-12-28T09:39:36.407Z Has data issue: false hasContentIssue false
  • English
  • Français

Ionic conductivity enhancement in Gd2Zr2O7 pyrochlore by Nd doping

Published online by Cambridge University Press:  31 January 2011

B.P. Mandal ,
S.K. Deshpande  and
A.K. Tyagi
B.P. Mandal
Affiliation:
Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
S.K. Deshpande
Affiliation:
University Grants Commission—Department of Atomic Energy (UGC-DAE) Consortium for Scientific Research, Bhabha Atomic Research Centre, Mumbai 400085, India
A.K. Tyagi*
Affiliation:
Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
*
a)Address all correspondence to this author. e-mail: [email protected]
Get access

Abstract

The pyrochlore compositions Gd2–yNdyZr2O7 (y = 0.0, 0.1, 0.4, 0.6, 1.0, 1.4, 1.6, and 2.0) were synthesized, and their ionic conductivity was determined (100 Hz–15 MHz, 622–696 K). The direct-current (dc) conductivity (σdc) varies upon Nd substitution at the Gd site, and a peaking effect in σdc was observed around y = 1.0. This indicates that a significant increase in conductivity can be obtained at moderately high temperatures by suitable doping at the Gd site with isovalent rare-earth ions like Nd. The extent of oxygen ion disorder determined from x-ray diffraction was found to decrease with increasing Nd content. The dc conductivity obeys the Arrhenius relation σdcT = σ0 exp(−E/kBT). The activation energy E and the preexponential factor σ0, which is a measure of the concentration of the mobile species, increase while going from the ordered Nd2Zr2O7 to the least ordered Gd2Zr2O7. These two processes presumably lead to the peaking of σdc at an intermediate Nd content. Our results also suggest that the cooperative motion of mobile ions does not contribute much to the increase in activation energy in this compound.

Keywords

Electrical propertiesX-ray diffraction (XRD)
Type
Articles
Information
Journal of Materials Research , Volume 23 , Issue 4 , April 2008 , pp. 911 - 916
Copyright
Copyright © Materials Research Society 2008

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1Subramanian, M.A., Aravamudan, G.SubbaRao, G.V.: Oxide pyrochlores: A review. Prog. Solid State Chem. 15, 55 1983CrossRefGoogle Scholar
2Weller, M.T., Hughes, R.W., Rouke, J., Knee, C.S.Reading, J.: The pyrochlore family: A potential panacea for the frustrated peroviskite chemist. Dalton Trans. 3032 2004CrossRefGoogle Scholar
3Wilde, P.J.Catlow, C.R.A.: Defects and diffusion in pyrochlore structured oxides. Solid State Ionics 112, 173 1998CrossRefGoogle Scholar
4Moreno, K.J., Guevara-Liceaga, M.A., Fuentes, A.F., Garcia-Barriocanal, J., Leon, C.Santamaria, J.: Room-temperature synthesis and conductivity of the pyrochlore type Dy 2(Ti1–yZry)2O7 (0 ⩽y ⩽1) solid solution. J. Solid State Chem. 179, 928 2006CrossRefGoogle Scholar
5Morenoa, K.J., Fuentesa, A.F., Garcia-Barriocanal, J., Leon, C.Santamaria, J.: Mechanochemical synthesis and ionic conductivity in the Gd2(Sn1–yZry)2O7 (0 ⩽ y ⩽ 1) solid solution. J. Solid State Chem. 179, 323 2006CrossRefGoogle Scholar
6Moon, P.K.Tuller, R.H.: Ionic conduction in the Gd2Ti2O7−Gd2Zr2O7 system. Solid State Ionics 28–30, 470 1988CrossRefGoogle Scholar
7Burggraaf, A.J., van Dijk, T.Verkerk, M.J.: Structure and conductivity of pyrochlore and fluorite type solid solutions. Solid State Ionics 5, 519 1981CrossRefGoogle Scholar
8Pirzada, M., Grimes, R.W., Minervini, L., Maguire, J.F.Sickafus, K.E.: Oxygen migration in A2B2O7 pyrochlores. Solid State Ionics 140, 201 2001CrossRefGoogle Scholar
9Kramer, S., Spears, M.Tuller, H.L.: Conduction in titanate pyrochlores: Role of dopant. Solid State Ionics 72, 59 1994CrossRefGoogle Scholar
10Heremans, C., Wuensch, B.J., Stalik, J.K.Prince, E.: Fast-ion conducting Y2(ZryTi1–y)2O7 pyrochlores: Neutron Rietveld analysis of disorder induced by Zr substitution. J. Solid State Chem. 117, 108 1995CrossRefGoogle Scholar
11Moreno, K.J., Mendonza-Suarez, G., Fuentes, A.F., Garcia-Barriocanal, J., Leon, C.Santamaria, J.: Cooperative oxygen ion dynamics in Gd2Ti2–yZryO7. Phys. Rev. B 71, 132301 2005CrossRefGoogle Scholar
12van Dijk, M.P., deVries, K.J.Burggraaf, A.J.: Oxygen ion and mixed conductivity in compounds with the fluorite and pyrochlore structure. Solid State Ionics 9–10, 913 1983CrossRefGoogle Scholar
13Mandal, B.P.Tyagi, A.K.: Homogeneity ranges and high temperature-XRD studies of Gd2–xNdxTi2O7 solid solutions. Mater. Sci. Eng., B 136, 46 2007CrossRefGoogle Scholar
14Mandal, B.P.Tyagi, A.K.: Preparation and high temperature-XRD studies on a Pyrochlore series with the general composition Gd2–xNdxZr2O7. J. Alloys Compd. 437, 260 2007CrossRefGoogle Scholar
15Shannon, R.D.: Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Crystallogr., Sect. A 32, 751 1976CrossRefGoogle Scholar
16Lian, X.T. Zu, Kutty, K.V.G., Chen, J., Wang, L.M.Ewing, R.C.: Ion irradiation induced amorphization of La2Zr2O7 pyrochlore. Phys. Rev. B 66, 054108 2002CrossRefGoogle Scholar
17Abdullah, M.H.Yussof, A.N.: Frequency dependence of the complex impedances and dielectric behavior of some Mg-Zn ferrites. J. Mater. Sci. 32, 5817 1997CrossRefGoogle Scholar
18Kutty, K.V. Govindan, Mathews, C.K., Rao, T.N.Varadaraju, U.V.: Oxide ion conductivity in some substituted rare earth pyrozirconates. Solid State Ionics 80, 99 1995CrossRefGoogle Scholar