A1 Refereed original research article in a scientific journal
Preparation of one to three unit cell thick YBa2Cu3O7-delta powders and investigation of their magnetic and microwave properties
Authors: Blinov E, Fleisher VG, Huhtinen H, Laiho R, Lahderanta E, Paturi P, Stepanov YP, Vlasenko L
Publisher: IOP PUBLISHING LTD
Publication year: 1997
Journal:: Superconductor Science and Technology
Journal name in source: SUPERCONDUCTOR SCIENCE & TECHNOLOGY
Journal acronym: SUPERCOND SCI TECH
Volume: 10
Issue: 11
First page : 818
Last page: 824
Number of pages: 7
ISSN: 0953-2048
DOI: https://doi.org/10.1088/0953-2048/10/11/005
Abstract
Nanocrystalline YBa2Cu3O7-delta powders have been prepared by a citrate gel modification of the sol-gel technique. Using a relatively low temperature, T = 790 degrees C, and (i) a process of extracting oxygen and reoxidizing the precursor powder or (ii) a sequence of vacuum annealing and prolonged heating in air, it was possible to avoid sintering of the particles. According to x-ray powder diffraction analysis the particles have orthorhombic structure pertinent to the YBa2Cu3O7 phase. Measurements made by atomic force microscopy show that they have flat shape with two maxima in the thickness distribution, one at 1.2 nm (approximate to 1c) and the other at 3.8 nm (approximate to 3c), corresponding to one or three orthorhombic unit cell lengths of the crystal. The average width of the particles is 40 nm. A similar value could be obtained from XRD measurements and the width of microwave absorption line around zero applied field. Superconducting properties of the powders were investigated with magnetization measurements.
Nanocrystalline YBa2Cu3O7-delta powders have been prepared by a citrate gel modification of the sol-gel technique. Using a relatively low temperature, T = 790 degrees C, and (i) a process of extracting oxygen and reoxidizing the precursor powder or (ii) a sequence of vacuum annealing and prolonged heating in air, it was possible to avoid sintering of the particles. According to x-ray powder diffraction analysis the particles have orthorhombic structure pertinent to the YBa2Cu3O7 phase. Measurements made by atomic force microscopy show that they have flat shape with two maxima in the thickness distribution, one at 1.2 nm (approximate to 1c) and the other at 3.8 nm (approximate to 3c), corresponding to one or three orthorhombic unit cell lengths of the crystal. The average width of the particles is 40 nm. A similar value could be obtained from XRD measurements and the width of microwave absorption line around zero applied field. Superconducting properties of the powders were investigated with magnetization measurements.
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