Saturation magnetization and band gap tuning in BiFeO$_3$ nanoparticles via co-substitution of Gd and Mn

TL;DR

This study explores how co-doping BiFeO$_3$ nanoparticles with Gd and Mn alters their structure, enhances magnetic properties at certain doping levels, and reduces their optical band gap and electrical resistivity.

Contribution

It provides new insights into how Gd and Mn co-substitution modifies the structural, magnetic, optical, and electrical properties of BiFeO$_3$ nanoparticles.

Findings

Enhanced saturation magnetization at 10% Mn doping

Reduction in optical band gap with co-doping

Structural transition from rhombohedral to orthorhombic

Abstract

In this investigation, Gd and Mn co-doped Bi$_{0.85}$Gd$_{0.15}$Fe$_{1-x}$Mn$_x$O$_3$ (x=0.0-0.15) nanoparticles have been prepared to report the influence of co-substitution on their structural, optical, magnetic and electrical properties. Due to simultaneous substitution of Gd and Mn in BiFeO$_3$, the crystal structure has been modified from rhombohedral (R3c) to orthorhombic (Pn21a) and the Fe-O-Fe bond angle and Fe-O bond length have been changed. For Mn doping up to 10 % in Bi$_{0.85}$Gd$_{0.15}$Fe$_{1-x}$Mn$_x$O$_3$ nanoparticles, the saturation magnetization (Ms) has been enhanced significantly, however, for a further increase of doping up to 15 %, the Ms has started to reduce again. The co-substitution of Gd and Mn in BiFeO$_3$ nanoparticles also demonstrates a strong reduction in the optical band gap energy and electrical resistivity compared to that of undoped BiFeO$_3$.