Conduction mechanism and magnetic behavior of dysprosium strontium iron garnet (DySrIG) nanocrystals

Garnet nanoparticles Dy2.8Sr0.2Fe5O12 (DySrIG) were prepared by citrate auto-combustion method and characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and differential thermal analysis (DTA). The suitable formation of this garnet in single phase was at 1100 °C with crystallite of size 95 nm. The Curie temperature of DySrIG is obtained at 610 K. The effective magnetic moment μeff was calculated experimentally and theoretically and they are compatible with each other. The dielectric constant ɛ′ increases from order 102 at room temperature to 104 at 850 K passing by four transition temperatures. The temperature dependence of the resistivity of DySrIG at different frequencies (f) 100 kHz ≤ f ≤ 5 MHz indicates the presence of 5 transition temperatures which are slightly different from those of ɛ′ data. The resistivity data are frequency independent at f < 1 MHz. The transition height is decreased by increasing the temperature from ≈5 MΩ cm at 320 K and 200 kHz to ≈20 Ω cm at 700 K. Accordingly, Dy2.8Sr0.2Fe5O12 (DySrIG) is recommended for the use in phase shifter, circulators and microwave applications.