Dielectric spectroscopy and magnetometry investigation of Gd-doped strontium titanate ceramics

authors	Tkach, A; Amaral, JS; Vitor, SAB; Vilarinho, PM
nationality	International
journal	JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
author keywords	SrTiO3; Doping; Dielectric relaxation; High-permittivity ceramics; Paramagnetism
keywords	THERMOELECTRIC PERFORMANCE; SRTIO3; RELAXATION; SR1-XCAXTIO3; BI-SRTIO3; RELAXOR; IONS
abstract	Structural, dielectric and magnetic properties of dense Gd-doped strontium titanate ceramics prepared by the conventional mixed oxide method are studied. Lattice parameter is found to decrease linearly in the Sr1-1.5xGd xTiO3 system, confirming the incorporation of Gd onto the Sr site of the perovskite lattice of strontium titanate up to x=0.05. Real and imaginary parts of the dielectric permittivity of Sr1-1.5xGd xTiO(3) ceramics exhibit a relaxation between 100 Hz and 1 MHz in the temperature range of 17-261k, slightly shifting to higher temperatures with increasing Gd content. Such dielectric behaviour is attributed to the relaxation of individual dipoles formed by off-centre displacement of Gd3+ ions on Sr sites in a highly polarizable lattice of strontium titanate. Other dielectric relaxations observed in Sr(1-1.5)xGd xTiO(3) from 125 to 300K are attributed to the oxygen vacancy related mechanisms. No magnetic anomaly but paramagnetic behaviour is observed for Sr1-1.5xGd xTiO(3) ceramics, indicating an absence of the magnetic order and hence magnetoelectric coupling.(C) 2017 Elsevier Ltd. All rights reserved.
publisher	ELSEVIER SCI LTD
issn	0955-2219
isbn	1873-619X
year published	2017
volume	37
issue	6
beginning page	2391
ending page	2397
digital object identifier (doi)	10.1016/j.jeurceramsoc.2017.02.011
web of science category	Materials Science, Ceramics
subject category	Materials Science
unique article identifier	WOS:000397359300009