resumo
The solid solutions of Bi1-x-yGdxBayFe1-yTiyO3 have been prepared via solid-state reaction method with the aim to obtain magnetoelectric coupling (i.e., linear relation between magnetization and electric field) at room temperature. Optimum calcination and sintering strategies for obtaining pure perovskite phase, high density ceramics and homogeneous microstructures have been determined. All the samples of the composition Bi1-x-yGdxBayFe1-yTiyO3 (x = 0.1 and y = 0.1, 0.2, and 0.3) reported in the present work are tetragonal at room temperature. The maximum ferroelectric transition temperature (T-c) of this system was 150-170 degrees C with the dielectric constant peak of 2300 at 100 kHz for y = 0.1. Above T-c the dielectric constant is decreasing up to a certain temperature and then increasing with temperature similar to that observed in other perovskites due to chemical inhomogeneities in both A and B sites of the ABO(3) cell. The variation of ferroelectric and magnetic properties was followed by piezoresponse force microscopy and vibrating sample magnetometer, respectively. Well-saturated piezoelectric loops were observed for all composition indicating room temperature ferroelectricity. (C) 2009 Elsevier B.V. All rights reserved.
palavras-chave
POLYCRYSTALLINE BIFEO3; ELECTRICAL-PROPERTIES; WEAK FERROMAGNETISM; CERAMICS; IMPEDANCE
categoria
Materials Science
autores
Rai, R; Bdikin, I; Valente, MA; Kholkin, AL
nossos autores
Andrei Kholkin
Investigador Principal
Radheshyam Rai
Bolseiro de pós-Doutoramentoagradecimentos
Radheshyam Rai is grateful to the Foundation for Science and Technology of Portugal (FCT) for financial support (grant SFRH/BPD/38001/2007).