Magnetic Spectra and Richter Aftereffect Relaxation in Zirconium-Doped Yttrium Iron Garnet Ferrites

The magnetic property and the magnetic aftereffect relaxation of zirconium (Zr)-doped yttrium iron garnet (YIG) Y₃Fe_(5-x)Zr_xO_12+x/2 (x=0 and 0.1) have been investigated. The ferrites were fabricated by the traditional solid-state reaction method. A crystalline structure and an elemental spectrum analysis were identified by powder X-ray diffraction and using X-ray photoelectron spectroscopy, respectively. Both of the ferrite samples reveal a single-phase garnet structure, but show a visible difference in permeability spectra between the two samples over a frequency of 1 MHz-1 GHz. It is verified that the Zr-doped YIG ferrite contains the contribution of Richter aftereffect relaxation to magnetic spectrum due to the existence of Fe²⁺ ions. The fitting of the permeability spectra in terms of the Richter model is in agreement with experimental data, which successfully accounts for the causes of magnetic losses observed at 1 MHz-1 GHz for the Zr-doped YIG ferrite.