Interaction of oxyfluorides of rare earth elements with fluorides having the fluorite structure

Gorbulev, V. A.; Федоров, П. П.; Соболев, Б. П.

doi:10.1016/0022-5088(80)90009-0

Cited by 17 publications

(5 citation statements)

References 14 publications

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“…Moreover, the BYF solid solution shows a textured component around the [111] direction, in agreement with previous observations . The Y content in the fluoride solid solution was determined from the measured lattice parameter, following a procedure previously reported …”

Section: Resultssupporting

confidence: 86%

Evolution of Metal-Trifluoroacetate Precursors in the Thermal Decomposition toward High-Performance YBa₂Cu₃O₇ Superconducting Films

et al. 2010

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A thorough analytical study on the thermal decomposition evolution of the metal-trifluoroacetate precursor toward high-performance YBa2Cu3O7 superconducting films is presented. Evolved gas analysis (EGA), using Fourier transform infrared spectroscopy (FTIR) and mass spectrometry (MS), as well as X-ray diffraction (XRD), was performed to determine the complete chemical decomposition reaction of the metal-trifluoroacetate precursors. It is noteworthy that, contrary to what had been previously described, HF was not detected in the released gas. Moreover, we present new processing conditions that successfully reduced and even eliminated the undesirable porosity of the pyrolyzed films. Focused-ion-beam (FIB) studies demonstrated that the formation of pores was related to a fast escape of the released gas during precursor decomposition. The oxygen partial pressure was determined to be a key parameter to control both the kinetics and thermodynamics of the decomposition reaction and, hence, the porosity. This is of great importance because dense films are required to achieve high critical current densities in YBa2Cu3O7 superconducting films.

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Section: Resultssupporting

confidence: 86%

Evolution of Metal-Trifluoroacetate Precursors in the Thermal Decomposition toward High-Performance YBa₂Cu₃O₇ Superconducting Films

et al. 2010

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“…MF 2 phases can dissolve up to dozens percents rare earth fluorides as well as alkali metal fluorides and oxygen (dissolving of the latter results in formation of oxyfluorides). Heterovalent replacement of fluorine by oxygen is known to cause formation of the relatively broad areas of homogeneity for the fluorite-type solid solutions based on Ca, Sr, Ba, Pb difluorides; and this is especially common for the systems that also contain rare earth cations (MF 2 -ROF systems) [309][310][311]231] and/or NaRF 4 [312]. Substitution of fluorine of oxygen in the crystal lattices of these phases results in essential variations of the unit cell parameters.…”

Section: Phase and Chemical Composition Of The Nanocrystalsmentioning

confidence: 99%

Transparent oxyfluoride glass ceramics

Федоров

Luginina

Попов

2015

Journal of Fluorine Chemistry

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289

123

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“…The first step of pyrohydrolysis of RF3 was shown in [36] to involve RF3-ZXOx oxyfluorides with small x values and not phases of the ROF or R 4 0 3 F 6 type, as was thought earlier. In contrast to MF 2 , oxygen partially dissolves in RF3 melts (see the MF 2 -ROF systems [37]). However, such solid solutions are unstable and partially decompose upon cooling.…”

Section: Chemical Processes During Mixture Preparation and Growthmentioning

confidence: 99%

“…However, such solid solutions are unstable and partially decompose upon cooling. A certain fraction of the oxygen remains dissolved in the single crystals [37]. Thus, the RF3 content can, up to definite concentrations that depend on the REE type, mask the oxygen impurity in the melt as RF3-ZXOx solid solutions.…”

Section: Chemical Processes During Mixture Preparation and Growthmentioning

confidence: 99%

Preparation of Single Crystals of the Nonstoicmometric Fluorite Phases M1-xRxF2+x (M = Ca, Sr, Ba; R = Rare Earth Elements) by the Bridgman-Stockbarger Method

Соболев¹,

Жмурова²,

Karelin³

et al. 1991

Growth of Crystals

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INTRODUCTIONResearch on the preparation and study of single-crystalline M 1 -N2+x (R = rare earth element, REE) materials with large deviations from stoichiometry began at the Institute of Crystallography of the Academy of Sciences of the USSR in 1963. The efforts were continued in cooperation with the chemistry staff of Moscow State University. Progress on the quest and preparation of crystals of nonstoichiometric fluorides for quantum electronics up to 1978 was reviewed in dissertations [2]. However, a large part of the data on growth of M 1 -N2+x single crystals is scattered over a large number of obscure publications.The purpose of the present article is to review and correlate all work published by us on the growth of M 1 -xRxf'2+x fluorite phase crystals.The uniqueness of this family of crystals and hence the unwavering interest in their preparation and study consists in the gross deviations from stoichiometry which permit fluorite structural types with heterovalent substitution of M2+ by R3+ (up to 50 mole % RF 3 ). Changes in the physical and physicochemical characteristics of the crystals are effected and controlled as a result of the gross nonstoichiometry. Mechanical, radiative, thermal, chemical, optical, transport, acoustic, and other structurally sensitive characteristics are affected.The M 1 -xRxf'2+x phases are the most striking with respect to nonstoichiometry and most feasible from the viewpoint of technological production among the more than 150 types of known fluorites with gross stoichiometric imbalance [1]. Numerically, they comprise a third of all known types (according to qualitative chemical compOSition) of fluorite-fluoride nonstoichiometric (two-component) phases.The scope of our program characteristically includes preparation of single crystalS of the M 1 -xRxf'2+x nonstoichiometric fluorite phases for the whole concentration region covering hundredths of a fraction of a percent to saturation, i.e., -50 mole % RF 3 . Numerous publications by other authors have appeared for REE trifluoride concentrations of 1-3 mole %. Review of these is a separate task. Few articles can be singled out on the preparation of single crystals with high contents of RF 3 . The most systematic of these should be mentioned [3][4][5][6]. In particular, the high content of heterovalent impurities in the CaF 2 structure is of prime 65 K. S. Bagdasarov et al. (eds.), Growth of Crystals

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Interaction of oxyfluorides of rare earth elements with fluorides having the fluorite structure

Cited by 17 publications

References 14 publications

Evolution of Metal-Trifluoroacetate Precursors in the Thermal Decomposition toward High-Performance YBa₂Cu₃O₇ Superconducting Films

Evolution of Metal-Trifluoroacetate Precursors in the Thermal Decomposition toward High-Performance YBa₂Cu₃O₇ Superconducting Films

Transparent oxyfluoride glass ceramics

Preparation of Single Crystals of the Nonstoicmometric Fluorite Phases M1-xRxF2+x (M = Ca, Sr, Ba; R = Rare Earth Elements) by the Bridgman-Stockbarger Method

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Interaction of oxyfluorides of rare earth elements with fluorides having the fluorite structure

Cited by 17 publications

References 14 publications

Evolution of Metal-Trifluoroacetate Precursors in the Thermal Decomposition toward High-Performance YBa2Cu3O7 Superconducting Films

Evolution of Metal-Trifluoroacetate Precursors in the Thermal Decomposition toward High-Performance YBa2Cu3O7 Superconducting Films

Transparent oxyfluoride glass ceramics

Preparation of Single Crystals of the Nonstoicmometric Fluorite Phases M1-xRxF2+x (M = Ca, Sr, Ba; R = Rare Earth Elements) by the Bridgman-Stockbarger Method

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Evolution of Metal-Trifluoroacetate Precursors in the Thermal Decomposition toward High-Performance YBa₂Cu₃O₇ Superconducting Films

Evolution of Metal-Trifluoroacetate Precursors in the Thermal Decomposition toward High-Performance YBa₂Cu₃O₇ Superconducting Films