Polymorphism in Ho2(MoO4)3

被引：7

作者：

Gonzalez-Silgo, C. ^{[1
]}

Guzman-Afonso, C. ^{[2
]}

Sanchez-Fajardo, V. M. ^{[3
]}

Acosta-Gutierrez, S. ^{[1
]}

Sanchez-Soares, A. ^{[1
]}

Torres, M. E. ^{[3
]}

Sabalisck, N. ^{[3
]}

Matesanz, E. ^{[4
]}

Rodriguez-Carvajal, J. ^{[5
]}

机构：

[1] Univ La Laguna, Dpto Fis Fundamental 2, E-38206 Tenerife, Spain

[2] Univ La Laguna, Dpto Fis Fundamental & Expt Elect & Sistemas, E-38206 Tenerife, Spain

[3] Univ La Laguna, Dpto Fis Basica, E-38206 Tenerife, Spain

[4] Univ Complutense Madrid, CAI Difracc Rayos X, E-28040 Madrid, Spain

[5] Inst Max Von Laue Paul Langevin, F-38042 Grenoble 9, France

来源：

POWDER DIFFRACTION | 2013年 / 28卷

关键词：

powder diffraction; phase transition; polymorphism; CRYSTAL-STRUCTURE;

D O I：

10.1017/S0885715613001176

中图分类号：

TB3 [工程材料学];

学科分类号：

0805 ; 080502 ;

摘要：

Two polymorphs of Holmium molybdate, known as beta'-phase and gamma-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 beta'-phase undergoes a transition to a-beta-phase and then to a gamma-phase. The gamma (hydrated)-phase, turns to the gamma (dehydrated)-phase and then to the beta-phase. Each sequence involves a reversible and an irreversible phase transition for Ho-2(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 beta'-phase and a negative one for the gamma-phase. Moreover, we have made a comparison of the obtained coefficients with previous results for other rare earth molybdates.

引用

页码：S33 / S40

页数：8

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