Magnetoelectric coupling in lead-free piezoelectric Li-x(K0.5Na0.5)(1-x)Nb1-yTayO3 and magnetostrictive CoFe2O4 laminated composites

Author(s)

Fu, Jiyong ^{[1, 2]} ; Santa Rosa, Washington ^{[1, 2]} ; M'Peko, Jean Claude ^[2] ; Alguero, Miguel ^[3] ; Venet, Michel ^[1]

Affiliation

^[1] Univ Fed Sao Carlos, Dept Fis, BR-13565905 Sao Carlos, SP - Brazil

^[2] Univ Sao Paulo, Inst Fis Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

^[3] CSIC, Inst Ciencia Mat Madrid, Plaza Murillo 2, E-28049 Madrid - Spain

• Document type: Journal article
• Source: Physics Letters A; v. 380, n. 20, p. 1788-1792, APR 29 2016.
• Web of Science Citations: 6

Abstract

To replace lead zirconium titanate in magnetoelectric (ME) composites owing to concerns regarding its toxicity, we investigate the ME coupling in bilayer composites comprising lead-free Li-x(K0.5Na0.5)(1-x)Nb1-yTayO3 (LKNNT) (piezoelectric) and CoFe2O4 (magnetostrictive) phases. We prepare the LKNNT ceramics and measure its piezoelectric coefficient d(31), a crucial ingredient determining ME couplings, for several Li (x = 0.03, 0.035, 0.04) and Ta (y = 0.15, 0.2, 0.25) concentrations, and find that the highest d(31) occurs at y = 0.2 for all the values of x studied here. We then evaluate both the transverse (alpha(E,31)) and the longitudinal (alpha(E,33)) low-frequency ME coupling coefficients of our composites, for each the above composition of (x, y). At x = 0.03, we find the usual scenario of alpha(E,31) and alpha(E,33), i.e., the strongest ME coupling occurs when d(31) is maximal, namely at y = 0.2. On the other hand, interestingly, we also obtain the strongest ME coupling when the LKNNT layer has a relatively weaker d(31), e.g., at y = 0.25 for x = 0.035 and y = 0.15 for x = 0.04, following from the interplay of d(31) and other ingredients (e.g., dielectric constant). Our calculated ME couplings, with alpha(E,31) in magnitude around twice of alpha(E,33), are comparable to those in lead-based composites. The effect of the volume fraction and interface parameter on the ME coupling is also discussed. (C) 2016 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 13/00134-7 - Obtaining and improvement of properties of lead free magnetoelectric composites
• Grantee: Michel Venet Zambrano
• Support Opportunities: Regular Research Grants