Room Temperature Magneto-dielectric coupling in the CaMnO3 modified NBT lead-free ceramics

TL;DR

This study demonstrates room temperature magnetodielectric coupling in CaMnO3-modified NBT ceramics, with the highest negative magnetodielectric effect observed at a specific composition, highlighting potential for multifunctional device applications.

Contribution

It reports the first observation of room temperature magnetodielectric coupling in lead-free NBT ceramics modified with CaMnO3, including detailed structural and dielectric analysis.

Findings

Maximum magnetodielectric effect of -3.69% at 100kHz and 5 kG field for x=0.06

Dielectric constant increased and loss decreased at x=0.03 composition

Phase transition temperature decreased with increasing CaMnO3 content

Abstract

The sol-gel prepared (1-x) Na0.5Bi0.5TiO3- (x) CaMnO3 (x=0, 0.03, 0.06, 0.12) compositions show a Rhombohedral (R3c) phase for x=0.06 while a mixed Rhombohedral (R3c) and orthorhombic (Pnma) phases for the x=0.12. The lattice volume consistently decreased with an increase in the CaMnO3 content. The phase transition temperature (Tc) decreased with an increase in the CaMnO3 compositions. The room temperature dielectric constant increased, and loss decreased for the x=0.03 composition due to a decrease in the oxygen vacancy and Bi loss confirmed by the valence state study (XPS). All the compositions show a variation of the room temperature dielectric property with an application of magnetic field confirming a magnetodielectric coupling. The x=0.06 composition shows the highest negative magnetodielectric constant (MD%) of 3.69 at 100kHz at an applied field of 5 kG.