Dielectric Properties of Y3Fe5O12 (YIG) Prepared at Different Molarities of NaOH

Abstract

In this study, Yttrium Iron Garnet (Y3Fe5O12) (YIG) powders were synthesized via co-precipitation method, followed by calcining the precipitates at 1100˚C. The garnets produced were obtained from aqueous iron and yttrium chloride mixtures using different molarities of NaOH (M=2, 3, 4 and 5) at pH=12. The phase formation and crystallography were investigated using X-ray diffraction (XRD), the morphology was investigated using transmission electron microscopy (TEM) and the dielectric properties were measured using an impedance analyzer in the frequency range 0.5 - 5MHz, in a temperature range 22 - 350˚C. X-ray diffraction peaks showed the formation of cubic YIG with lattice parameter varying between 12.334 and 12.339 Å. The grain size, measured from TEM images, decreased with the increase of the molarity of NaOH. Plots of the real part of the dielectric constant ε′, the imaginary part of the dielectric constant ε'', loss tangent tan δ and ac conductivity σac as functions of frequency and temperature, respectively, were obtained. It was observed that the highest values of the dielectric constant were obtained in the 2M sample.