Enhanced magnetoelectricity in bismuth substituted SrFe_(12)O_(19) hexaferrite

摘要

M-type bismuth doped strontium hexaferrite Sr1-xBixFe12O19 (x=0, 0.01, and 0.02) is prepared by the sol-gel auto-combustion method and studied for magnetoelectricity. The lattice of the x=0.01 sample is found to be highly strained compared to the other two compositions. The enhancement of strain is also accompanied by an increase in magnetization by 6%. Impedance and modulus spectroscopy studies suggest a transition in relaxation mechanism from grain dominated (below 150K) to grain boundary dominated (above 150K). The grain related capacitance for x=0.01 is found to be similar to 50nF, and this value is similar to 10 times higher than the other two samples. The linear magnetoelectric coefficient alpha/d (in mVcm(-1) Oe(-1)) for the parent x = 0 sample is found to be 0.33 at 125 K, and this value decreases gradually to 0.27 at 300 K. The x = 0.01 sample displayed the highest (even 10% higher than the x = 0 sample) value of alpha/d at low temperature. Unfortunately, the increased value of alpha/d is also accompanied by a drastic reduction in its magnitude for temperatures higher than 200 K, due to the increased electrical conduction which in x = 0.01 is similar to 94% higher than the parent. Published under license by AIP Publishing.