Optical band gap tuning, zero dielectric loss and room temperature ferromagnetism in (Ag/Mg) co-doped SnO2 compounds for spintronics applications

Abstract

Co-doped oxide materials with non-magnetic elements have recently emerged as a viable material for spintronic applications. The goal of this study is to see how Ag–Mg co-doping affects the structural, dielectric, optical, and magnetic characteristics of SnO2 compounds. The solid-state reaction method was used to prepare the samples of Sn0.94-yAg0.06MgyO2 (with y = 0, 0.03, 0.06, 0.09, 0.12) in the polycrystalline form. All of the observed X-ray diffraction peaks can be attributed to SnO2's tetragonal rutile type structure. The average crystallite size (Sc) was found to be in the region of 49–63 nm using Debye Scherrer's formula. The SEM micrograph study revealed the particles size in the range of 70–120 nm for these compounds. The EDS analysis revealed that all the elements are evenly distributed in the co-doped SnO2 compounds. The Maxwell-Wagner model was used to analyse and explain the frequency dependent behavior of dielectric constant (εr), dielectric loss (tanδ), and ac conductivity of all Ag–Mg co-doped materials. The study of the optical property of the prepared samples indicates band gap narrowing with increasing concentration of Ag–Mg co-doping. Room temperature ferromagnetism with ultra-low coercivity is evidenced from the M − H curves measurements.