Hostname: page-component-78c5997874-mlc7c Total loading time: 0 Render date: 2024-11-14T15:18:00.820Z Has data issue: false hasContentIssue false
  • English
  • Français

Polymorphism in Ho2(MoO4)3

Published online by Cambridge University Press:  14 November 2013

C. González-Silgo ,
C. Guzmán-Afonso ,
V. M. Sánchez-Fajardo ,
S. Acosta-Gutiérrez ,
A. Sánchez-Soares ,
M. E. Torres ,
N. Sabalisck ,
E. Matesanz  and
J. Rodríguez-Carvajal
C. González-Silgo*
Affiliation:
Dpto. Física Fundamental II, Universidad de La Laguna, Avda. Astrofísico Fco. Sánchez, s/n, 38206 La Laguna, Tenerife, Spain
C. Guzmán-Afonso
Affiliation:
Dpto. Física Fundamental y Experimental, Electrónica y Sistemas, Universidad de La Laguna, Avda. Astrofísico Fco. Sánchez, s/n, 38206 La Laguna, Tenerife, Spain
V. M. Sánchez-Fajardo
Affiliation:
Dpto. Física Básica, Universidad de La Laguna, Avda. Astrofísico Fco. Sánchez, s/n, 38206 La Laguna, Tenerife, Spain
S. Acosta-Gutiérrez
Affiliation:
Dpto. Física Fundamental II, Universidad de La Laguna, Avda. Astrofísico Fco. Sánchez, s/n, 38206 La Laguna, Tenerife, Spain
A. Sánchez-Soares
Affiliation:
Dpto. Física Fundamental II, Universidad de La Laguna, Avda. Astrofísico Fco. Sánchez, s/n, 38206 La Laguna, Tenerife, Spain
M. E. Torres
Affiliation:
Dpto. Física Básica, Universidad de La Laguna, Avda. Astrofísico Fco. Sánchez, s/n, 38206 La Laguna, Tenerife, Spain
N. Sabalisck
Affiliation:
Dpto. Física Básica, Universidad de La Laguna, Avda. Astrofísico Fco. Sánchez, s/n, 38206 La Laguna, Tenerife, Spain
E. Matesanz
Affiliation:
C.A.I. Difracción de Rayos X, Universidad Complutense de Madrid, 28040 Madrid, Spain
J. Rodríguez-Carvajal
Affiliation:
Institut Laue-Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9, France
*
a) Electronic mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Two polymorphs of Holmium molybdate, known as β'-phase and γ-phase, were prepared by solid state reaction with different thermal treatments. These polycrystalline samples have been studied for the first time by X-ray thermodiffractometry from room temperature up to 1300 K. We found that the initial β'-phase undergoes a transition to a β-phase and then to a γ-phase. The γ (hydrated)-phase, turns to the γ (dehydrated)-phase and then to the β-phase. Each sequence involves a reversible and an irreversible phase transition for Ho2(MoO4)3. Both polymorphs have remarkable physical properties like nonlinear optics, ferroelectricity and negative thermal expansion. We have calculated the linear expansion coefficients of both phases. We have obtained a positive coefficient for the β'-phase and a negative one for the γ-phase. Moreover, we have made a comparison of the obtained coefficients with previous results for other rare earth molybdates.

Keywords

powder diffractionphase transitionpolymorphism
Type
Technical Articles
Information
Powder Diffraction , Volume 28 , Supplement S2 , September 2013 , pp. S33 - S40
Copyright
Copyright © International Centre for Diffraction Data 2013 

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

Abrahams, S. C. and Bernstein, J. L. (1966). “Crystal Structure of the Transition-Metal Molybdates and Tungstates. II. Diamagnetic Sc2(WO4)3 ,” J. Chem. Phys. 45, 2745–2752.Google Scholar
Brixner, L. H., Barkley, J. R. and Jeitschko, W. (1979). Handbook on the Physics and Chemistry of Rare Earth (Amsterdam: North-Holland).Google Scholar
Evans, J. S. O and Mary, T. A. (2000). “Structural phase transitions and negative thermal expansion in Sc2(MoO4)3 ,” Int. J. Inorg. Mater. 2, 143–151.Google Scholar
Gates, S. D. and Lind, C. (2007). “Polymorphism in yttrium molybdate Y2Mo3O12 ,” J. Solid State Chem. 180, 3510–3514.Google Scholar
González Silgo, C., Torres, M. E., Guzmán-Afonso, C., Sabalisck, N., Lozano-Gorrín, A. D., González-Platas, J., Matesanz, E., Rodríguez-Carvajal, J. (2011). Crystal structure and non-linear properties of A2(MoO4)3 (Report Proposal 5-23-626). Grenoble, France: Institut Laue-Langevin user portal. https://club.ill.fr/cv/servlet/ReportFind Google Scholar
Guzmán-Afonso, C., González-Silgo, C., González-Platas, J., Torres, M. E., Lozano-Gorrín, A. D., Sabalisck, N., Sánchez-Fajardo, V., Campo, J. and Rodríguez-Carvajal, J. (2011). “Structural investigation of the negative thermal expansion in yttrium and rare earth molybdates,” J. Phys.: Condens. Matter 23, 325402 (9pp).Google Scholar
Jeitschko, W. (1973). “Crystal structure of La2(MoO4)3, a new ordered defect Scheelite type,” Acta Crystallogr., Sect. B: Struct. Crystallogr. Cryst. Chem. 29, 2074–2081.Google Scholar
Jeitschko, W. (1972). “A Comprehensive X-ray Study of the Ferroelectric-Ferroelastic and Paraeleetric-Paraelastic Phases of Gd2(MoO4)3 ,” Acta Crystallogr., Sect. B: Struct. Crystallogr. Cryst. Chem. 28, 60–76.Google Scholar
Kim, S., Lee, G. S., Shrout, T. R. and Venkataramani, S. (1991). “Fabrication of fine-grain piezoelectric ceramics using reactive calcination,” J. Mater. Sci. 26, 4411–4415.Google Scholar
Kojima, S. and Nakamura, T. (1978). “Electro-optical properties of gadolinium molybdate,” Phys. Rev. B 18, 453–458.Google Scholar
Le Bail, A. (2005). “Whole powder pattern decomposition methods and applications: A retrospection,” Powder Diffr. 20, 316–326.Google Scholar
Rodríguez-Carvajal, J. (1993). “Recent advances in magnetic structure determination by neutron powder diffraction,” Physica B 192, 55–69.Google Scholar
Templeton, D. H. and Zalkin, A. (1963). “Crystal structure of europium tungstate,” Acta Crystallogr. 16, 762–766.Google Scholar