Rare-earth iron garnets (RIG, R = Y, Tb and Lu) were sintered at 1350 °C.

A similar Fe²⁺/Fe³⁺ ratio (∼27/73) was measured in different RIGs.

Electron hopping between FeO₆ and FeO₄ resulted in a large dielectric response.

Debye-type dielectric relaxation was dominant at room temperature.

Maxwell-Wagner effect had a significant contribution at elevated temperature.