Effect of Nd doping on the magnetic properties of charge-ordered Bi_(0.6-x)Nd_xCa_(0.4)MnO_3 (0.0≤x ≤0.6) perovskitemanganites

摘要

We have studied structure, magnetic and transport properties of polycrystalline Bi_(0.6-x)Nd_xCa_(0.4)MnO_3 (x = 0.0,0.1, 0.2, 0.3, 0.4, 0.5 and 0.6). Substitution of Nd at Bi sites induces a strong interplay between the magnetic and charge ordering. The charge-ordering temperature (T_(co)) decreases with increasing x. Further, the antiferromagnetic ordering temperature (7n) increases sharply at both extremes and remains nearly constant for x = 0.2-0.4. At T ＜ T(N) a transition to a metamagnetic glass-like state is also seen. Nd doping also leads to enhancement in the magnetic moment and a concomitant decrease in resistivity up to x = 0.3 and then an increase in resistivity up to x = 0.5. Furthermore, Nd doping promotes an antiferromagnetic to ferromagnetic type fluctuation in the materials at room temperature, as evidenced by the change in the value of the paramagnetic Curie temperature. We find that the local lattice distortion induced by the size mismatch between the A-site cations and the 6s2 character of Bi~(3+) lone pair electrons explains the observed peculiarity in magnetic and transport properties of Nd-doped Bi_(0.6-x)Nd_xCa_(0.4)MnO_3.