화학공학소재연구정보센터
Journal of the American Ceramic Society, Vol.102, No.12, 7414-7427, 2019
Control of electrical leakage in magneto-electric gallium ferrite via aliovalent substitution
One of the challenges with magnetoelectric multiferroic gallium ferrite (GaFeO3 or GFO) is its high electrical leakage whose control is essential for realizing any prospect of its practical applications. In this manuscript, we report on the effect of aliovalent doping at Fe site in magnetoelectric gallium ferrite in controlling its electrical leakage via tuning of its grain and grain-boundary characteristics. Polycrystalline pure as well as zinc (Zn2+) and zirconium (Zr4+)-doped gallium ferrite samples were synthesized by conventional solid-state reaction method. Contrary to defect chemistry predictions, Zn2+ substituted samples show marked reduction in the electrical leakage with 10% Zn2+ substituted samples showing two orders of magnitude lower leakage current while Zr4+-doped samples exhibit increased electrical leakage. This is supported by higher activation energy for conduction in the low frequency regime for Zn2+-doped samples while nearly temperature independent conduction for Zr4+-doped GFO samples. The results suggest that while Zn2+ doping leads to increase in resistance of the grain boundaries leading to lower conductivity, Zr4+ doping leads to opposite effect.