Thermal Expansion of EuF2+x Single Crystals and Their Thermal Stability

被引：3

作者：

Karimov, D. N. ^{[1
]}

Grebenev, V. V. ^{[1
]}

Ivanova, A. G. ^{[1
]}

Khaydukov, K. V. ^{[1
]}

Sidorov, A. A. ^{[2
]}

Kulchenkov, E. A. ^{[2
]}

Popov, P. A. ^{[2
]}

Sobolev, B. P. ^{[1
]}

机构：

[1] Russian Acad Sci, Fed Sci Res Ctr Crystallog & Photon, Shubnikov Inst Crystallog, Moscow 119333, Russia

[2] Petrovskii Bryansk State Univ, Bryansk 241036, Russia

来源：

CRYSTALLOGRAPHY REPORTS | 2018年 / 63卷 / 04期

基金：

俄罗斯基础研究基金会;

关键词：

RARE-EARTH TRIFLUORIDES; FLUORITE PHASES; EUROPIUM; CONDUCTIVITY; TEMPERATURES; EU; GD; SM; ND;

D O I：

10.1134/S1063774518040107

中图分类号：

O7 [晶体学];

学科分类号：

0702 ; 070205 ; 0703 ; 080501 ;

摘要：

Thermal expansion of an EuF2.136 nonstoichiometric crystal with the fluorite structure type (Eu (0.864) (2+) Eu (0.136) (3+) F-2.136, lattice parameter 5.82171(5) ) has been experimentally investigated in the temperature range of 9-500 K. The coefficient of thermal expansion is alpha = 15.8 x 10(-6) K-1 at T = 300 K. The observed anomalies in the behavior of the coefficient of thermal expansion at T > 400 K are related to the oxidation processes with partition of Eu2+ ions. It is established by differential scanning calorimetry that the onset temperature of EuF2 + x oxidation in air is 430 K and that this process occurs in three stages. X-ray diffraction analysis shows that the oxidation is accompanied by the formation of a phase mixture based on two modifications of the Eu (1-y) (3+) Eu (y) (2+) F3-y solid solution with the structure types of tysonite (LaF3), orthorhombic beta-YF3 phase, and europium oxyfluorides of variable composition EuO1-x F1 + 2x , with dominance of the latter.

引用

页码：614 / 620

页数：7

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