Tailoring of microstructure, magnetic properties and charge carrier dynamics of YIG nanoparticles by Gd doping

Abstract

Effect of gadolinium doping on growth mechanism, microstructure, magnetic properties and conductivity relaxation behavior of sol-gel prepared yttrium iron garnet (YIG) nanoparticles is studied in detail. Rietveld microstructural analysis of XRD data confirms the growth of single phase nanocrystalline YIG. Gd doping created oxygen vacancies inside the system which played an important role in controlling transport properties. Switching field distribution (S.F.D.) and Law of Approach to saturation (L.A.S.) techniques were adapted to analyze magnetic properties which delineate an improvement of coercivity and anisotropy constant. Impedance spectroscopy revealed the grain contributions only to the conduction process and frequency dependent conductivity follows universal power law. Harviliak-Negami (H.N.) formalism was adapted to analyze the modulus data in the frequency domain. Scaling of conductivity and electrical modulus data established that the conduction and relaxation process are temperature and composition independent. Non-Debye type correlative motion of charge carriers was established via analysis of decay function of electric field ϕ(t) inside the material which was described by Kohlrausch-Williams-Watts (K.W.W.) function. Improvements of magnetic and electrical properties in the prepared system can be beneficial for different applications.