Low dielectric constant and signature of ferroelectric nature in transition metal (Co, Ni, Cu)-doped Mg0.5 Zn0.5 Al2O4 aluminates

Abstract

This paper throws light on the preparation of transition metal-doped Mg0.5-xTMxZn0.5Al2O4 (x=0, 0.05 and TM=Co, Ni, Cu) aluminates via solid-state reaction route. The X-ray diffraction characterization analysis confirmed that all the samples have crystallized into the psuedocubic phase having space group Fd3m and were single phased. The incorporation of transition metals viz. Co2+, Ni2+, Cu2+ in the Mg0.5Zn0.5Al2O4 matrix does not result in the appearance of new peaks or any considerable shift in diffraction peaks within the limits of XRD experimentation. This infers homogeneous dispersion of dopants at the Mg-site which is attributed to nearly same ionic radii of the dopants to that of Mg-site in Mg0.5Zn0.5Al2O4. Lattice structure, bonding nature and hence the spinel formation were verified through Raman scattering technique. The compositional verification was carried out via energy dispersive analysis of X-rays (EDAX). The surface morphology and hence the microstructural studies were carried out using field emission scanning electron microscopy (FESEM). The synthesized Mg0.5-xTMxZn0.5Al2O4 (x=0, 0.05 and TM=Co, Ni, Cu) aluminate samples were tested for polarization studies keeping their insulating nature into consideration and they displayed a sign of well-behaved P-E loop.