Bi位掺La对Bi-2212粉体结构和性质的影响

Effect of Lanthanide Substitution for Bismuth on the Structure and Property of Bi_2Sr_2CaCu_2O_δ

以硝酸盐为前驱物,利用溶胶-凝胶(sol-gel)法,制备了(Bi1-xLax)2Sr2CaCu2Oδ(x=0,0.1,0.2,0.3,0.4)粉体。通过X射线衍射(XRD)和透射电镜(TEM),对晶体结构进行了表征;采用SQUID和标准四引线法,对该粉体磁化强度随温度变化(M-T)和电阻随温度变化(R-T)曲线进行了测试,研究了Bi部分被La替代导致Bi系超导体结构和电磁特性的变化。结果表明,随着La掺杂量逐渐增加,晶格常数c未发生变化,而a,b逐渐变大,且沿b轴方向的调制周期减小;样品表现出抗磁性和反铁磁、超导和半导体特性共存、竞争的独特性质。

Sol-gel method was adopted to prepare the （Bi1-xLax）2Sr2CaCu2Oδ （x=0, 0., 0., 0., 0.4） powders using different nitrates as precursors. Structural characterization was carried out by X-ray diffraction （XRD） and Transmission Electron Microscopy （TEM）. The temperature dependence of resistance R （T） was measured by the standard four-probe technique, and the magnetization M （T） was recorded using a Quantum Design PPMS superconducting quantum interference device （SQUID） magnetometer. The results show that with increasing of La content, the lattice parameters of a and b are decreased, and the modulation period along b axis becomes short. Meanwhile, with the increasing of La content, the character of diamagnetism state and antiferromagnetic state being coexisted and competed is investigated.