A series of Bi2-xLaxSr2CaCu2O8+δ (x = 0.00, 0.05, 0.10, 0.15, and 0.20) ceramic samples were synthesized by co-precipitation (CP) method. In this work, the influence of La doping on the phase evolution, microstructure, critical transition temperature, and flux pinning properties of Bi-2212 was investigated. The results indicate that La doping significantly promotes the formation of the Bi-2212 phase. As the La content increases, the a and b axis lengths of Bi-2212 structure gradually increase, while the c-axis length decreases. The La doping will introduce compressive stress into the Bi-O layers. Meanwhile, the modulation structure in Bi-2212 becomes enhanced with La substitution by decreasing the modulation period, which is effectively explained by the extra oxygen model. Furthermore, the critical transition temperatures (<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10854_2025_14917_Article_IEq1.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="44" /> </InlineMediaObject> <EquationSource Format="TEX">$T_c^{onset}$</EquationSource> <EquationSource Format="MATHML"><math> <msubsup> <mi>T</mi> <mi>c</mi> <mrow> <mi mathvariant="italic">onset</mi> </mrow> </msubsup> </math></EquationSource> </InlineEquation>) initially increases and then decreases with higher La doping levels, reaching a maximum <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10854_2025_14917_Article_IEq1.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="44" /> </InlineMediaObject> <EquationSource Format="TEX">$T_c^{onset}$</EquationSource> <EquationSource Format="MATHML"><math> <msubsup> <mi>T</mi> <mi>c</mi> <mrow> <mi mathvariant="italic">onset</mi> </mrow> </msubsup> </math></EquationSource> </InlineEquation> of 85.9 K for the sample with x = 0.15. The sample also exhibits the strongest flux pinning capability.

Effects of La doping on the structure and superconducting properties of Bi-2212

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发表日期：

2025年5月15日

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Jiaxin Chang,
Fang Yang,
Shengnan Zhang,
Hao Cao,
Yifan Zhang,
Guoqing Liu,
Jixing Liu,
Chengshan Li,
Jianfeng Li,
Pingxiang Zhang

摘要

A series of Bi_2-xLa_xSr₂CaCu₂O_8+δ (x = 0.00, 0.05, 0.10, 0.15, and 0.20) ceramic samples were synthesized by co-precipitation (CP) method. In this work, the influence of La doping on the phase evolution, microstructure, critical transition temperature, and flux pinning properties of Bi-2212 was investigated. The results indicate that La doping significantly promotes the formation of the Bi-2212 phase. As the La content increases, the a and b axis lengths of Bi-2212 structure gradually increase, while the c-axis length decreases. The La doping will introduce compressive stress into the Bi-O layers. Meanwhile, the modulation structure in Bi-2212 becomes enhanced with La substitution by decreasing the modulation period, which is effectively explained by the extra oxygen model. Furthermore, the critical transition temperatures ( $T_c^{onset}$ $T_{c}^{onset}$ ) initially increases and then decreases with higher La doping levels, reaching a maximum $T_c^{onset}$ $T_{c}^{onset}$ of 85.9 K for the sample with x = 0.15. The sample also exhibits the strongest flux pinning capability.