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Anti-site disorder and physical properties in microwave synthesized RE2Ti2O7 (RE = Gd, Ho) pyrochlores

Authors :
Adrián Andrada-Chacón
Emilio Morán
Alejandro Gómez-Pérez
Daniel Muñoz-Gil
Javier Sánchez-Benítez
Rainer Schmidt
María Teresa Azcondo
Ulises Amador
Jesús Prado-Gonjal
Source :
RSC Advances. 5:85229-85241
Publication Year :
2015
Publisher :
Royal Society of Chemistry (RSC), 2015.

Abstract

In this work we report on the microwave assisted synthesis of nano-sized Gd2Ti2O7 (GTO) and Ho2Ti2O7 (HTO) powders from the RE2Ti2O7 pyrochlore family (RE = rare earth). Synchrotron X-ray powder diffraction was used to study RE–Ti cationic anti-site defects with concentrations that decrease in both samples with increasing temperature starting from 1100 °C, and the defects disappear at 1400 °C. SQUID magnetometry measurements revealed that GTO shows a predominantly anti-ferromagnetic structure, whereas HTO exhibits magnetic saturation and a ferromagnetic component at low temperature. Impedance spectroscopy data revealed strongly increased ionic oxygen vacancy conduction in HTO ceramic pellets as compared to GTO, which may be associated with a higher degree of oxygen vacancy disorder. This argument was supported by Raman spectroscopy data.

Details

ISSN :
20462069
Volume :
5
Database :
OpenAIRE
Journal :
RSC Advances
Accession number :
edsair.doi...........a3f5120855de8b2fad03c1e0fe11b8fd