摘要
In this paper,effect of Gd^3+was investigated on structural,magnetic,and dielectric properties of Mn0.5Zn0.5GdxFe2–xO4(x=0,0.025,0.050,0.075,and 0.1)nanoparticles prepared by facile coprecipitation method.X-ray diffraction(XRD)studies confirmed the single cubic spinel phase for all the samples and showed that lattice parameter(aexp)was found to increase from 8.414 to 8.446Åwith the substitution of Gd3+ions due to their larger ionic radii than the replaced Fe3+ions.Shape and size of developed nanoparticles were studied using transmission electron microscopy(TEM)and found that particle size decreased from 31.06 to 21.12 nm for x=0–0.1.Magnetic properties showed that maximum magnetization decreased from 39.21 to 23.59 emu/g,and Curie temperature decreased from 192 to 176℃with increase in x from 0 to 0.1 due to weakening of superexchange interaction.Dielectric parameters like dielectric constant(e¢ande¢),dielectric loss(tanδ),AC conductivity(σac),and impedance(Z¢and Z¢)as a function of frequency and composition were analyzed and discussed.It was found thate¢,e¢,σac,and tanδvalues decreased with Gd substitution,which has been explained based on Maxwell–Wagner theory and hopping mechanism of electrons between Fe3+and Fe2+ions at octahedral sites.Nyquist plots for all the developed compositions showed single semi-circular arc which indicate the dominant effect of grain boundaries.
