The effect of Gd-doping on the charge ordering state of Bi 0.3−xGd xCa 0.7MnO 3 (0≤ x≤0.30)

Abstract

The effect of Gd-doping on the charge ordering (CO) state in perovskite-type manganates Bi 0.3− x Gd x Ca 0.7MnO 3 with x=0, 0.02, 0.05, 0.1, 0.3 has been investigated by transport and magnetic property measurements. It is found that CO temperature ( T CO ) and antiferromagnetic (AFM) ordering temperature T N occurring below T CO decrease obviously with increasing Gd-doping level. Accompanying the variation of T CO , the increased magnetization and the decreased resistivity are observed. In addition, the increased magnetic inhomogeneity has been also observed in the samples based on the difference between the zero-field-cooling (ZFC) magnetization M ZFC and field-cooling (FC) magnetization M FC , which is ascribed to the competition between ferromagnetic (FM) phase induced by Gd-doping and CO AFM phase. The experimental results indicate that the Bi 3+ lone pair electron with 6s 2 character plays a dominating role on the CO state of Bi 0.3Ca 0.7MnO 3.