Effects of Bi3+ doping on charge ordering and high magnetic field phase diagram of Nd0.6-xBixCa0.4MnO3

Abstract

We report the doping effects and pulsed high magnetic field-induced charge ordering to ferromagnetic phase transitions in manganites Nd0.6-xBixCa0.4MnO3 (0 ≤ x ≤ 0.4). The experimental results reveal that the charge ordering is significantly enhanced upon Bi3+ doping, and the charge ordering temperature increases with increasing Bi3+ content. With applying pulsed high magnetic field, the charge ordering phase collapses into ferromagnetic phase through a metamagnetic transition. The phase diagram of Nd0.6-xBixCa0.4MnO3 has been determined by the high magnetic field studies, in which the charge ordering and ferromagnetic phase boundary is clearly figured out. The critical fields for melting the charge ordering phase of Nd0.6-xBixCa0.4MnO3 increase significantly with increasing Bi3+ content, which is revealed to reach up to 33.5 T for the sample with x = 0.3. Based on the hybridization between Bi-6s orbitals and O-2p orbitals, we assume that the 6s2 lone-pair character of Bi3+ plays a crucial role in favoring the charge ordering in Nd0.6-xBixCa0.4MnO3 (0 ≤ x ≤ 0.4).