Enhanced magnetic and ferroelectric properties in Cr doped Bi_2Fe_4O_9 ceramics

摘要

Single phase Bi_2Fe_(4(1-x))Cr_(4x)O_9 (0 ≤ x ≤ 0.08) ceramics are prepared by a modified Pechini method to investigate the effect of Cr doping on magnetic and ferroelectric properties. The results show that both the magnetic and ferroelectric properties are strongly dependent on Cr doping. With the introduction of Cr ions, Bi_2Fe_4O_9 ceramics change from antiferromagnetism to weak FM at room temperature, in accompaniment with the enhancement of ferroelectric properties. The remnant magnetization and polarization enhance monotonically from 0.014 emu/g and 0.103 μC/cm~2 for x = 0.02 sample to 0.025 emu/g and 0.53 μC/cm~2 for x= 0.08 sample, respectively. The improvement of magnetic and ferroelectric properties should be mainly related to the suppression of inhomogeneous magnetic spin structure and the reduction of electric leakage by Cr doping. These results suggest that Cr doping can adjust the magnetic and ferroelectric properties of Bi_2Fe_4O_9 ceramics, which is a promising candidate for room temperature multiferroics.