Crystal structure and dielectric properties of LaYbO3

FETEIRA, Antonio, GILLIE, Lisa J., ELSEBROCK, Ralf and SINCLAIR, Derek C. (2007). Crystal structure and dielectric properties of LaYbO3. Journal of the American Ceramic Society, 90 (5), 1475-1482.

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Official URL: http://dx.doi.org/10.1111/j.1551-2916.2007.01549.x
Link to published version:: 10.1111/j.1551-2916.2007.01549.x

Abstract

The crystal structure and dielectric properties of LaYbO3 ceramics prepared by the mixed-oxide route have been investigated. Rietveld refinements performed on X-ray and neutron diffraction data show the room-temperature structure to be best described by the orthorhombic Pnma space group [a=6.02628(9) Å, b=8.39857(11) Å, and c=5.82717(7) Å; Z=4, and theoretical density, Dx=8.1 g/cm3] in agreement with electron diffraction experiments. LaYbO3 ceramics fired at 1600°C for 4 h attain ∼97% of Dx and their microstructures consist of randomly distributed equiaxed grains with an average size of ∼8 μm. Conventional transmission electron microscopy shows densification to occur in the absence of a liquid phase and reveals domain-free grains. The relative permittivity, ɛr, of LaYbO3 ceramics at radio frequencies is ∼26 in the range ∼10–300 K; however, a small dielectric anomaly is detected at ∼15 K. At room temperature and microwave frequencies, LaYbO3 ceramics exhibit ɛr∼26, Q×fr∼20 613 GHz (at 7 GHz), and τf∼−22 ppm/K. Q×fr show complex subambient behavior, decreasing from a plateau value of ∼20 000 GHz between ∼300 and 200 K to a second plateau value of ∼6000 GHz at ∼90 K before decreasing to <1000 GHz at ∼10 K. The large decrease in Q×fr at low temperature may be related to the onset of antiferromagnetism at ∼2.7 K.

Item Type: Article
Research Institute, Centre or Group: Materials and Engineering Research Institute > Structural Materials and Integrity Research Centre > Centre for Corrosion Technology
Identification Number: 10.1111/j.1551-2916.2007.01549.x
Depositing User: Hilary Ridgway
Date Deposited: 06 Jun 2012 16:11
Last Modified: 06 Jun 2012 16:11
URI: http://shura.shu.ac.uk/id/eprint/5334

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