Maintenance of integrity between phases in PMN-PT/NFO hot-forged particulate magnetoelectric composites

Abstract

The influence of hot forging temperature on microstructure and magnetoelectric properties in (0.8)Pb(Mg_1/3Nb_2/3)_0.68Ti_0.32O₃+(0.2) NiFe₂O₄ particulate composites were investigated. Samples sintered at intermediate stage of sintering show inter-diffusion and high conductivity resulting in low magnetoelectric coupling related to charge leak current. Composites sintered before the initial stage of sintering show apparent density aprox. 90% and low magnetoelectric coefficient due to poor mechanical coupling between phases. Composites sintered at initial stage of sintering showed improved apparent density (>98%) and resistivity (>10⁸ Ωm). These characteristics allowed an enhancement of magnetoelectric coupling (∼6 mV/cmOe) due to control of inter-diffusion added to enhancement of the microstructural properties.

Keywords:

• PMN-PT
• NFO
• composites
• magnetoelectric effect
• hot-forging method

Additional information

Funding

The authors would like to thank the CNPq (grant# 409531/2016-2 and 477354/213-0)), CAPES/COFECUB, Capes-Procad 2013 (grant #3012/2014) and FAPESP (grant #2008/040250) Brazilian agencies for financial support, Ms. L. C. Nogueira and Ms. N. A. Zanardi for technical support and XRD analyses.