Dielectric relaxations of yttrium iron garnet ceramics over a broad temperature range.

Dielectric response of Y₃Fe₅O₁₂ ceramics was investigated over broad temperature and frequency ranges. Three dielectric relaxations were identified in the temperature range from 125 to 620 K. A Debye-type dielectric relaxation at low temperatures (125–320 K) with an activation energy of 0.29 eV is shown to originate from the carrier hopping process between Fe²⁺ and Fe³⁺. In a higher temperature range (320–620 K), a low frequency (f≤10 kHz) dielectric relaxation with an activation energy of 0.84 eV most likely arises from the inhomogeneous structure, such as grain boundaries. Another dielectric relaxation in a wider frequency range has a similar activation energy with conduction (E_a=1.00 eV) suggests that it can be attributed to the conduction [ABSTRACT FROM AUTHOR]