Coexistence of superconductivity and complex 4 f magnetism in Eu0.5Ce0.5BiS2F.
EuBiS2F is a self-doped superconductor due to the mixed valence of Eu. Here we report that, with the Ce substitution for Eu by 50 at.%, the material exhibits ferromagnetic ordering at 8 K for the Ce-4 f moment, superconductivity at 2.2 K in the BiS2 layers and possibly antiferromagnetic ordering at 2.1 K for the Eu-4 f spins. The Eu valence is essentially divalent with the Ce incorporation. We tentatively interpret the coexistence of ferromagnetism and superconductivity by considering different Bi-6p orbitals that are responsible for the superconductivity itself and for mediating the ferromagnetic interaction, respectively. We argue that the antiferromagnetic ordering of the Eu-4 f spins is most likely due to a magnetic dipole-dipole interaction.
Department of Physics, Zhejiang University, Hangzhou 310027, People's Republic of China.
Hui-Fei
HF
Zhai
Pan
P
Zhang
Zhang-Tu
ZT
Tang
Jin-Ke
JK
Bao
Hao
H
Jiang
Chun-Mu
CM
Feng
Zhu-An
ZA
Xu
Guang-Han
GH
Cao