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arXiv · 1608.04410

Mn-doping induced ferromagnetism and enhanced superconductivity in Bi_4-x Mn_x O_4 S_3 (0.075 < = x < = 0.15)

Zhenjie Feng·Xunqing Yin·Yiming Cao·Xianglian Peng·Tian Gao·Chuan Yu·Jingzhe Chen·Baojuan Kang·Bo Lu·Juan Guo·Qing Li·Wei-Shiuan Tseng·Zhongquan Ma·Chao Jing·Shixun Cao·Jincang Zhang·N. -C. Yeh
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Abstract

We demonstrate that Mn-doping in the layered sulfides Bi_4O_4S_3 leads to stable Bi_4-x Mn_x O_4 S_3 compounds that exhibit both long-range ferromagnetism and enhanced superconductivity for 0.075 < = x < = 0.15, with a possible record superconducting transition temperature (T_c) = 15 K among all BiS_2-based superconductors. We conjecture that the coexistence of superconductivity and ferromagnetism may be attributed to Mn-doping in the spacer Bi2O2 layers away from the superconducting BiS_2 layers, whereas the enhancement of T_c may be due to excess electron transfer to BiS_2 from the Mn4+/Mn3+-substitutions in Bi_2O_2. This notion is empirically corroborated by the increased electron-carrier densities upon Mn doping, and by further studies of the Bi_4-x A_x O_4 S_3 compounds (A = Co, Ni; x = 0.1, 0.125), where the T_c values remain comparable to that of the undoped Bi_4O_4S_3 system (= 4.5 K) due to lack of 4+ valences in either Co or Ni ions for excess electron transfer to the BiS_2 layers. These findings therefore shed new light on feasible pathways to enhance the T_c values of BiS_2-based superconductors.

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Zhenjie Feng, Xunqing Yin, Yiming Cao, Xianglian Peng, Tian Gao, Chuan Yu, Jingzhe Chen, Baojuan Kang, Bo Lu, Juan Guo, Qing Li, Wei-Shiuan Tseng, Zhongquan Ma, Chao Jing, Shixun Cao, Jincang Zhang, N. -C. Yeh. 2016-08-15. Mn-doping induced ferromagnetism and enhanced superconductivity in Bi_4-x Mn_x O_4 S_3 (0.075 < = x < = 0.15). https://doi.org/10.1103/physrevb.94.064522

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