Thermal tuning of electrical and dielectric characteristics of Mn-doped Zn_0.95Fe_0.05O dilute magnetic semiconductors

Structural and hence the electrical properties of transition metal doped ZnO-based dilute magnetic semiconductors can effectively be tuned thermally for their potential utilization in high temperature modern day spintronic devices. In this work, we investigate the effect of Mn doping on structural and its consequent effects on the electrical characteristics of Zn_0.95−xMn_xFe_0.05O (x = 0.00, 0.01, 0.02, 0.03, 0.04 and 0.05) synthesized using sol–gel auto-combustion. X-ray diffraction analysis indicated that the synthesized samples had the pure wurtzite-type hexagonal crystal structure. Average crystallite size as determined using Scherrer’s formula was decreased with the increase of Mn doping while the porosity was increased. Temperature dependent dielectric measurements revealed that dielectric constant and dielectric loss was increased by increasing the temperature for Mn-doped samples. The conductivity was also enhanced with increasing temperature due to the enhanced evolution of charge carriers between the grains. Temperature dependent impedance spectroscopy confirmed that resistance and reactance were inverse function of the temperature revealing negative temperature coefficient of resistance. Nyquist plot shows semi-circular behavior attributed to the grain boundary effect.