Effect of magnetic ion doping on structural, electric and relaxor properties of Pb (Fe2/3W1/3) O3 multiferroic ceramics

Bárbara Fraygola,José Antônio Eiras

doi:10.1590/1516-1439.287814

Abstract

Single-phase Pb(Fe2/3W1/3)O3 (PFW) multiferroic ceramics doped with magnetic ions were fabricated using a modified B-site precursor method. Dielectric response was investigated over a wide range of temperature and frequency. Doping did not modify the characteristic temperatures (T C, T N) and the order at ferroelectric phase transition, keeping the relaxor properties. However, the leakage current and resistivity of PFW have been improved with the substitutions: 1 mol% MnO2 addition caused a significant increase in the electric resistivity of PFW ceramics, around 7 orders of magnitude.

Highlights

As is well known, PZT (Pb(ZrxTi1-x)O3) as a ferroelectric system can be improved by changing the composition in order to make it suitable for technological applications, such as piezoelectric transducers, pyroelectric detectors, and nonvolatile ferroelectric memories[1,2,3]
The influence of the added dopants on the temperature and absolute values of the maximum dielectric permittivity, corresponding to the ferroelectric–paraelectric transition is consistent with the results reported by Miranda,[12] who revealed that Co doping in PFW, at the level of 1-10 at %, caused a shift to lower temperatures in the transition temperature
We summarize the principal results obtained from all measurement as follows: i) A two-stage solid-state reaction turned out to be appropriated for the formation of the majoritarian PFW phase as well for “pure” PFW as for magnetic doped ceramics, with low percentage of spurious phase and high density (>98%); ii) Doping decrease the lattice parameter but no systematic variation of grain size was observed; iii) All doping increased DC electric resistivity of PFW ceramics

Summary

Introduction

PZT (Pb(ZrxTi1-x)O3) as a ferroelectric system can be improved by changing the composition in order to make it suitable for technological applications, such as piezoelectric transducers, pyroelectric detectors, and nonvolatile ferroelectric memories[1,2,3]. Multiferroic materials, in which electric and magnetic orderings coexist in a single phase, have attracted the attention of the scientific community[4,5]. An interesting peculiarity of the PFW system, by comparison with other multiferroic materials, is caused by the presence of magnetic ions Fe3+ with occupancy of 66.66% of the B-octahedral sites of the perovskite cells, In this context, the present work aims to study the influence of magnetic ions addition on the phase transition and relaxor characteristics of PFW ceramics. Dielectric properties at high frequencies (microwave region) permitted us to characterize the dielectric response and magnetic phase transitions without conductive influences

Methods

Results

Conclusion